Add experimental Snap package

[istori1]

Description

Add snap package of sunshine.

Screenshot

Issues Fixed or Closed

Type of Change

• [x] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have added or updated the docstring/documentation-blocks for new or existing methods/components

[ReenigneArcher]

Todo (in separate PR):

• [ ] configure snapcraft.yml by cmakelists (similar to flatpak, appimage, macports, aur)... see https://github.com/LizardByte/Sunshine/pull/388#discussion_r988390154

[ReenigneArcher]

Todo:

• [ ] configure snapcraft.yml by cmakelists (similar to flatpak, appimage, macports, aur)... see https://github.com/LizardByte/Sunshine/pull/388#discussion_r988390154
• [ ] update docs
  • [ ] add installation section for snap https://github.com/istori1/Sunshine/blob/patch-2/docs/source/about/installation.rst#linux
  • [ ] update this section (https://github.com/istori1/Sunshine/blob/patch-2/docs/source/about/usage.rst#linux) does snap handle this automatically?
  • [ ] any special considerations for snap? https://github.com/istori1/Sunshine/blob/patch-2/docs/source/about/usage.rst#considerations

[ReenigneArcher]

If you are still wanting this added, can you update your PR, otherwise please close it.

To merge, the above Todo list will need to be completed as well.