Improve documentation (#598, #1105)

 * rework/simplify server configuration/requirements pages (consolidate/simplify SSL/TLS/apache configuration)
 * update index.md introduction
 * remove external images (badges)
 * Fix COPYING link and documentation links
 * Update features list
 * dedpulicate information
 * remove server-requirements.md and move relevant doc to other files
 * TODO: rework nginx configuration (single configuration example, with commented out blocks for special cases)
 * TODO: consolidate download/install/configuration pages
 * remove blank lighttpd configuration section
 * remove Required? column for composer packages, all libraries are mandatory
 * php 7.2 compatibilty
 * clarify that certbot binary and paths may vary depending on install method

1 files changed, 44 insertions, 30 deletions

diff --git a/doc/md/index.md b/doc/md/index.md
index 224070cb..21a63d3c 100644
--- a/doc/md/index.md
+++ b/doc/md/index.md
@@ -1,19 +1,27 @@
 # [Shaarli](https://github.com/shaarli/Shaarli/) documentation
 
-Here you can find some info on how to use, configure, tweak and solve problems with your Shaarli.
+The personal, minimalist, super-fast, database free, bookmarking service.
+
+Do you want to share the links you discover?
+Shaarli is a minimalist link sharing service that you can install on your own server.
+It is designed to be personal (single-user), fast and handy.
+
+<!--- TODO screenshots --->
 
-For general info, read the [README](https://github.com/shaarli/Shaarli/blob/master/README.md).
+Here you can find some info on how to use, configure, tweak and solve problems with your Shaarli.
+For general information, read the [README](https://github.com/shaarli/Shaarli/blob/master/README.md).
 
 If you have any questions or ideas, please join the [chat](https://gitter.im/shaarli/Shaarli) (also reachable via [IRC](https://irc.gitter.im/)), post them in our [general discussion](https://github.com/shaarli/Shaarli/issues/308) or read the current [issues](https://github.com/shaarli/Shaarli/issues).
+
 If you've found a bug, please create a [new issue](https://github.com/shaarli/Shaarli/issues/new).
 
 If you would like a feature added to Shaarli, check the issues labeled [`feature`](https://github.com/shaarli/Shaarli/labels/feature), [`enhancement`](https://github.com/shaarli/Shaarli/labels/enhancement), and [`plugin`](https://github.com/shaarli/Shaarli/labels/plugin).
 
-_Note: This documentation is available online at https://shaarli.readthedocs.io/, and locally in the `doc/html/` directory of your Shaarli installation._
+* [GitHub project page](https://github.com/shaarli/Shaarli)
+* [Online documentation](https://shaarli.readthedocs.io/) (this page)
+* [Latest Shaarli releases](https://github.com/shaarli/Shaarli/releases)
+* [Changelog](https://github.com/shaarli/Shaarli/blob/master/CHANGELOG.md)
 
-[![Join the chat at https://gitter.im/shaarli/Shaarli](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/shaarli/Shaarli)
-[![Bountysource](https://www.bountysource.com/badge/team?team_id=19583&style=bounties_received)](https://www.bountysource.com/teams/shaarli/issues)
-[![Docker repository](https://img.shields.io/docker/pulls/shaarli/shaarli.svg)](https://hub.docker.com/r/shaarli/shaarli/)
 
 ### Demo
 
@@ -22,6 +30,9 @@ It runs the latest development version of Shaarli and is updated/reset daily.
 
 Login: `demo`; Password: `demo`
 
+<!---- TODO review everything below this point --->
+
+
 ## Features
 
 Shaarli can be used:
@@ -42,26 +53,31 @@ Shaarli can be used:
 - to feed other social networks, blogs... using RSS feeds and external services (dlvr.it, ifttt.com ...).
 
 ### Interface
+
 - minimalist design (simple is beautiful)
 - FAST
 - ATOM and RSS feeds
 - views:
-    - paginated link list
+    - paginated link list (with image and video thumbnails)
     - tag cloud
-    - picture wall: image and video thumbnails
+    - picture wall: image and video thumbnails (with lazy loading)
     - daily: newspaper-like daily digest
     - daily RSS feed
 - permalinks for easy reference
 - links can be public or private
+- thumbnail generation for images and video services
+- URL cleanup: automatic removal of `?utm_source=...`, `fb=...`
 - extensible through [plugins](https://shaarli.readthedocs.io/en/master/Plugins/#plugin-usage)
 
-### Tag, view and search your links!
+### Tag, view and search your links
+
 - add a custom title and description to archived links
 - add tags to classify and search links
-    - features tag autocompletion, renaming, merging and deletion
+  - features tag autocompletion, renaming, merging and deletion
 - full-text and tag search
 
 ### Easy setup
+
 - dead-simple installation: drop the files, open the page
 - links are stored in a file
     - compact storage
@@ -70,23 +86,19 @@ Shaarli can be used:
 - import and export links as Netscape bookmarks
 
 ### Accessibility
-- Firefox bookmarlet to share links in one click
+
+- bookmarlet to share links in one click
 - support for mobile browsers
-- works with Javascript disabled
+- degrades gracefully with Javascript disabled
 - easy page customization through HTML/CSS/RainTPL
 
 ### Security
-- bruteforce-proof login form
-- protected against [XSRF](http://en.wikipedia.org/wiki/Cross-site_request_forgery)
-and session cookie hijacking
-
-### Goodies
-- thumbnail generation for images and video services:
-dailymotion, flickr, imageshack, imgur, vimeo, xkcd, youtube...
-    - lazy-loading with [bLazy](http://dinbror.dk/blazy/)
-- [PubSubHubbub](https://code.google.com/p/pubsubhubbub/) protocol support
-- URL cleanup: automatic removal of `?utm_source=...`, `fb=...`
+
 - discreet pop-up notification when a new release is available
+- bruteforce protection on the login form
+- protected against [XSRF](http://en.wikipedia.org/wiki/Cross-site_request_forgery) and session cookie hijacking
+
+<!---- TODO Limitations --->
 
 ### REST API
 
@@ -95,28 +107,30 @@ Easily extensible by any client using the REST API exposed by Shaarli.
 See the [API documentation](http://shaarli.github.io/api-documentation/).
 
 ## About
+
 ### Shaarli community fork
+
 This friendly fork is maintained by the Shaarli community at https://github.com/shaarli/Shaarli
 
 This is a community fork of the original [Shaarli](https://github.com/sebsauvage/Shaarli/) project by [Sébastien Sauvage](http://sebsauvage.net/).
 
-The original project is currently unmaintained, and the developer [has informed us](https://github.com/sebsauvage/Shaarli/issues/191)
-that he would have no time to work on Shaarli in the near future.
-The Shaarli community has carried on the work to provide
-[many patches](https://github.com/shaarli/Shaarli/compare/sebsauvage:master...master)
-for [bug fixes and enhancements](https://github.com/shaarli/Shaarli/issues?q=is%3Aclosed+)
-in this repository, and will keep maintaining the project for the foreseeable future, while keeping Shaarli simple and efficient.
+The original project is currently unmaintained, and the developer [has informed us](https://github.com/sebsauvage/Shaarli/issues/191) that he would have no time to work on Shaarli in the near future.
+
+The Shaarli community has carried on the work to provide [many patches](https://github.com/shaarli/Shaarli/compare/sebsauvage:master...master) for [bug fixes and enhancements](https://github.com/shaarli/Shaarli/issues?q=is%3Aclosed+) in this repository, and will keep maintaining the project for the foreseeable future, while keeping Shaarli simple and efficient.
+
 
 ### Contributing
+
 If you'd like to help, please:
 - have a look at the open [issues](https://github.com/shaarli/Shaarli/issues)
 and [pull requests](https://github.com/shaarli/Shaarli/pulls)
 - feel free to report bugs (feedback is much appreciated)
-- suggest new features and improvements to both code and [documentation](https://github.com/shaarli/Shaarli/wiki)
+- suggest new features and improvements to both code and [documentation](https://github.com/shaarli/Shaarli/tree/master/doc/md/)
 - propose solutions to existing problems
 - submit pull requests :-)
 
 
 ### License
-Shaarli is [Free Software](http://en.wikipedia.org/wiki/Free_software). See [COPYING](COPYING) for a detail of the contributors and licenses for each individual component.
+
+Shaarli is [Free Software](http://en.wikipedia.org/wiki/Free_software). See [COPYING](https://github.com/shaarli/Shaarli/blob/master/COPYING) for a detail of the contributors and licenses for each individual component. A list of contributors is available [here](https://github.com/shaarli/Shaarli/blob/master/AUTHORS).