Initial version of sphinx documentation and...

- remove ubuntu 21.04 from CI (end of life)
- adjust matrix strategy for clang.yml
- Use lessons learned from RetroArcher on localize.yml, crowdin.yml, and locale.py
- Add end of life comments to Dockerfiles
- Adjust dependency order in Dockerfiles

docs/source/about/installation.rst

@@ -0,0 +1,84 @@
+:github_url: https://github.com/SunshineStream/Sunshine/tree/nightly/docs/source/about/installation.rst
+
+Installation
+============
+The recommended method for running Sunshine is to use the `binaries`_ bundled with the `latest release`_.
+
+Binaries
+--------
+Binaries of Sunshine are created for each release. They are available for Linux, and Windows.
+Binaries can be found in the `latest release`_.
+
+.. Todo:: Create binary package(s) for MacOS. See `here <https://github.com/SunshineStream/Sunshine/issues/61>`_.
+
+.. Tip:: Some third party packages also exist. See
+   :ref:`Third Party Packages <about/third_party_packages:third party packages>`.
+
+Docker
+------
+.. Todo:: Docker images of Sunshine are planned to be included in the future.
+   They will be available on `Dockerhub.io`_ and `ghcr.io`_.
+
+Linux
+-----
+
+AppImage
+^^^^^^^^
+.. image:: https://img.shields.io/github/issues/sunshinestream/sunshine/pkg:appimage?logo=github&style=for-the-badge'
+   :alt: GitHub issues by-label
+
+#. Download and extract `sunshine-appimage.zip`
+
+Debian Packages
+^^^^^^^^^^^^^^^
+.. image:: https://img.shields.io/github/issues/sunshinestream/sunshine/os:linux:debian?logo=github&style=for-the-badge'
+   :alt: GitHub issues by-label
+
+#. Download the corresponding `.deb` file, e.g. ``sunshine-ubuntu_20_04.deb``
+#. ``sudo apt install -f <downloaded deb file>``, e.g. ``sudo apt install -f ./sunshine-ubuntu_20_04.deb``
+
+Red Hat Packages
+^^^^^^^^^^^^^^^^
+.. image:: https://img.shields.io/github/issues/sunshinestream/sunshine/os:linux:fedora?logo=github&style=for-the-badge'
+   :alt: GitHub issues by-label
+
+#. Download the corresponding `.rpm` file, e.g. ``sunshine-fedora_35.rpm``
+#. ``sudo rpm -i <downloaded rpm file>``, e.g. ``sudo rpm -i ./sunshine-fedora_35.rpm``
+
+.. Note:: If this is the first time installing.
+
+      .. code-block:: bash
+
+         sudo usermod -a -G input $USER
+         sudo reboot now
+
+.. Tip:: Optionally, run Sunshine in the background.
+
+      .. code-block:: bash
+
+         systemctl --user start sunshine
+
+MacOS
+-----
+.. image:: https://img.shields.io/github/issues/sunshinestream/sunshine/os:macos?logo=github&style=for-the-badge'
+   :alt: GitHub issues by-label
+
+#. Install `MacPorts <https://www.macports.org>`_
+#. Download the `Portfile <https://github.com/SunshineStream/Sunshine/blob/master/Portfile>`_ from this repository to
+   ``/tmp``
+#. In a terminal run ``cd /tmp && sudo port install``
+#. The first time you start Sunshine, you will be asked to grant access to screen recording and your microphone.
+
+Windows
+-------
+.. image:: https://img.shields.io/github/issues/sunshinestream/sunshine/os:windows:10?logo=github&style=for-the-badge'
+   :alt: GitHub issues by-label
+
+.. image:: https://img.shields.io/github/issues/sunshinestream/sunshine/os:windows:11?logo=github&style=for-the-badge'
+   :alt: GitHub issues by-label
+
+#. Download and extract ``sunshine-windows.zip``
+
+.. _latest release: https://github.com/SunshineStream/Sunshine/releases/latest
+.. _Dockerhub.io: https://hub.docker.com/repository/docker/sunshinestream/sunshine
+.. _ghcr.io: https://github.com/orgs/SunshineStream/packages?repo_name=sunshine