Add guide for screego (#1800)

* [screego] add guide for screego

* [screego] add logo

* [screego] add a note on how to prevent someone from entering an existing room

* [screego] minor change

* [screego] create the screego.config file and fix an incorrect config value

* [screego] change screego to Screego

* [screego] add more suitable tags that are already used by other guides

* [screego] change the secret in the example

* [screego] add a note regarding SCREEGO_TURN_PORT_RANGE

* [screego] update version numbers

* [screego] use a web backend

source/guide_screego.rst

@@ -0,0 +1,144 @@
+.. highlight:: console
+
+.. author:: no-one <https://github.com/no-one>
+
+.. tag:: lang-go
+.. tag:: ports
+.. tag:: screen-sharing
+.. tag:: self-hosting
+.. tag:: STUN
+.. tag:: TURN
+.. tag:: WebRTC
+
+.. sidebar:: Logo
+
+  .. image:: _static/images/screego.png
+      :align: center
+
+#######
+Screego
+#######
+
+.. tag_list::
+
+Screego_ is an open-source software that provides screen sharing via WebRTC. A demo can be found at https://app.screego.net.
+
+----
+
+.. note:: For this guide you should be familiar with the basic concepts of
+
+  * :manual:`Firewall ports <basics-ports>`
+  * :manual:`supervisord <daemons-supervisord>`
+  * :manual:`web-backends <web-backends>`
+
+License
+=======
+
+All relevant legal information can be found here:
+
+  * https://github.com/screego/server/blob/master/LICENSE
+
+Prerequisites
+=============
+
+.. include:: includes/open-port.rst
+
+Installation
+============
+
+Create a new directory, enter the directory you just created, download the latest version, unpack the archive, delete the archive afterwards, make the binary executable and create the file ``screego.config`` as a copy of the file ``screego.config.example``:
+
+.. note:: Replace ``1.11.1`` with the version of the `latest release`_.
+
+.. code-block:: console
+
+ [isabell@stardust ~]$ mkdir ~/screego
+ [isabell@stardust ~]$ cd ~/screego
+ [isabell@stardust screego]$ wget "https://github.com/screego/server/releases/download/v1.11.1/screego_1.11.1_linux_amd64.tar.gz"
+ [isabell@stardust screego]$ tar xvf screego_1.11.1_linux_amd64.tar.gz
+ [isabell@stardust screego]$ rm screego_1.11.1_linux_amd64.tar.gz
+ [isabell@stardust screego]$ chmod +x screego
+ [isabell@stardust screego]$ cp screego.config.example screego.config
+ [isabell@stardust screego]$
+
+Configuration
+=============
+
+Configure Screego
+-----------------
+
+.. note:: You can use the following command to generate your own ``SCREEGO_SECRET``: ``tr -dc A-Za-z0-9 < /dev/urandom | head -c 40; echo``
+
+.. warning:: Replace ``isabell`` with your username, ``<YOUR_SECRET>`` with your secret and ``40132`` with your port!
+
+The following settings must be adjusted in the ``~/screego/screego.config``:
+
+::
+
+ SCREEGO_EXTERNAL_IP=dns:isabell.uber.space
+
+ SCREEGO_SECRET=<YOUR_SECRET>
+ 
+ SCREEGO_TURN_ADDRESS=0.0.0.0:40132
+
+.. note::
+  Please have a look at "`NAT Traversal`_" on the official project page. In most cases STUN should be sufficient, but if TURN is used it is necessary to open more ports and specify them under ``SCREEGO_TURN_PORT_RANGE`` in the ``screego.config`` file. For the number of ports to be opened, the following currently applies approximately: ``shared video streams * users in the room * 4``
+  There is also a `bug in the TURN server`_ which results in not all connections being properly cleaned up. This means that even more ports may be required.
+
+Setup daemon
+------------
+
+Create ``~/etc/services.d/screego.ini`` with the following content:
+
+::
+
+ [program:screego]
+ directory=%(ENV_HOME)s/screego/
+ command=%(ENV_HOME)s/screego/screego serve
+ autostart=yes
+ autorestart=yes
+ startsecs=30
+             
+.. include:: includes/supervisord.rst
+
+If it's not in state RUNNING, check your configuration.
+
+Setup web backend
+-----------------
+
+.. note:: The default port for Screego is ``5050``.
+
+.. include:: includes/web-backend.rst
+
+.. warning:: Replace ``isabell`` with your username!
+
+If Screego is running, you can now find the website at ``https://isabell.uber.space``.
+
+Best practices
+==============
+
+Security
+--------
+
+Keep the software up to date.
+
+If you do not want third parties to be able to create new rooms on your server, then set ``SCREEGO_AUTH_MODE=all`` in the ``screego.config`` file so that a login with username and password is mandatory (the command ``./screego hash -h`` can help you to create a user file required for this). If you want to prevent someone from entering an existing room via the direct link that exists for each room, choose a more complex room ID.
+
+Updates
+=======
+
+.. note:: Check the `GitHub release page <latest release_>`_ regularly to stay informed about the newest version.
+
+To update the software, download the latest version and replace all files (``LICENSE``, ``README.md``, ``screego`` and ``screego.config.example``). Also check if there are any changes in the ``screego.config.example`` compared to your currently used ``screego.config``.
+
+.. _Screego: https://screego.net
+.. _firewall: https://manual.uberspace.de/basics-ports.html
+.. _latest release: https://github.com/screego/server/releases
+.. _NAT Traversal: https://screego.net/#/nat-traversal
+.. _bug in the TURN server: https://github.com/pion/turn/issues/246
+
+----
+
+Tested with Screego 1.11.1, Uberspace 7.16.1
+
+.. author_list::