build(flatpak): separate dependencies into sub-modules

[ReenigneArcher]

Description

Separate flatpak dependencies into sub-modules. This is prep for flathub/dev.lizardbyte.app.Sunshine#36

In another PR, dependencies will be built from their upstream source control instead of from https://salsa.debian.org. This was used temporarily since it is what is used on flathub, but note that any patches applied there are not present here.

Screenshot

Issues Fixed or Closed

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

Branch Updates

LizardByte requires that branches be up-to-date before merging. This means that after any PR is merged, this branch
must be updated before it can be merged. You must also
Allow edits from maintainers.

• I want maintainers to keep my branch updated

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 9.23%. Comparing base (3b95397) to head (7d00c3d).

Additional details and impacted files

@@          Coverage Diff           @@
##           master   #2818   +/-   ##
======================================
  Coverage    9.23%   9.23%           
======================================
  Files          97      97           
  Lines       17440   17440           
  Branches     8314    8314           
======================================
  Hits         1611    1611           
  Misses      12946   12946           
  Partials     2883    2883           

Flag	Coverage Δ
Linux	6.99% <ø> (ø)
Windows	4.53% <ø> (ø)
macOS-12	10.32% <ø> (ø)
macOS-13	10.24% <ø> (+0.01%)	⬆️
macOS-14	10.55% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

see 25 files with indirect coverage changes