ci(flatpak): sync with flathub

[ReenigneArcher]

Description

This PR is a replacement for #3251 (some git hiccup when I was trying to work on my fork happened)

Sync with flathub.

Todo:

• Add README.md for flathub.
• verify notes in metainfo.xml
• automate releases section in metainfo.xml
• package files requires to create flathub repo into a release asset.
• automate PRs into flathub on stable releases.
• Test in forks
  • PR automation
  • Make PR into Flathub to ensure their tests pass, see: chore: Update dev.lizardbyte.app.Sunshine to v2024.1004.232441 flathub/dev.lizardbyte.app.Sunshine#182
  • build cannot access network
    • cache npm deps
    • do not use fetch content for boost
    • tests cannot access the network

Screenshot

Issues Fixed or Closed

• Resolves package is out of sync with upstream LizardByte/Sunshine flathub/dev.lizardbyte.app.Sunshine#36

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update (updates to dependencies)
• Documentation update (changes to documentation)
• Repository update (changes to repository files, e.g. .github/...)

Checklist

• My code follows the style guidelines of this project
• 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 in code docstring/documentation-blocks for new or existing methods/components

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 9.74%. Comparing base (e90b71c) to head (09064ce).
Report is 90 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #3259    +/-   ##
=======================================
  Coverage    9.73%   9.74%            
=======================================
  Files         101     101            
  Lines       17972   17972            
  Branches     8417    8417            
=======================================
+ Hits         1750    1751     +1     
+ Misses      13480   13330   -150     
- Partials     2742    2891   +149     

Flag	Coverage Δ
Linux	7.27% <ø> (ø)
Windows	5.10% <ø> (ø)
macOS-13	10.55% <ø> (+0.02%)	⬆️
macOS-14	10.01% <ø> (ø)

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see 25 files with indirect coverage changes