Add Libqrcodegencpp on Linux and add its finder

[tytan652]

Description

Related to:

• Add Libqrcodegencpp obs-deps#182
• Add CMake find modules for Libqrcodegen C and C++ PatTheMav/cmake-finders#2

obs-websockets PR requires:

• Drop Ubuntu 20.04, related CI will failed because of an API break from Libqrcodegen between 1.5.0 (20.04) and 1.7.0 (22.04) (header file name change) with obs-websocket PRs.

Dependency of:

• base,deps,src: Replace qr submodule by prefix/system install obs-websocket#1143

Add Libqrcodegencpp to Ubuntu script and Flatpak and its finder since not all distribution of the library comes with a CMake package.

Please, review the finder on the cmake-finders repo PR.

Motivation and Context

Reduce to zero the number of submodule in obs-websocket repo.

How Has This Been Tested?

Generated a QR code with obs-websocket with obs-websocket build with the library and not the submodule on Linux.

Test binaries available on a PR on my fork: tytan652#13

Types of changes

• CI and CMake additions

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[RytoEX]

This has a merge conflict. Can this be merged independently of obsproject/obs-deps#182?

[tytan652]

This has a merge conflict.

Fixed

Can this be merged independently of obsproject/obs-deps#182?

Yes, only the obs-websocket PR does not.

[RytoEX]

Looks okay at a glance.

@GeorgesStavracas Flatpak parts look okay?
@PatTheMav CMake finders look okay?

[GeorgesStavracas]

Flatpak change is fine 👍

[PatTheMav]

Did I understand it right that we need this finder despite manually adding a CMake project for the library at obs-deps? Does the separate CMake project repo add everything but proper CMake project generation?

[tytan652]

Did I understand it right that we need this finder despite manually adding a CMake project for the library at obs-deps? Does the separate CMake project repo add everything but proper CMake project generation?

I quote myself from the PR description:

…and its finder since not all distribution of the library comes with a CMake package

Edit: So blame Ubuntu and/or Debian.

[PatTheMav]

Should be fine even with Windows and macOS variants shipped as CMake packages (local FindModules take precedence). Once Linux is updated to the CMake path, the finder probably needs to be moved to the Linux-specific subdirectory (just like the Windows-specific Python finder) as it will not be needed by the other platforms.

[RytoEX]

It seems that #8327 introduced a minor merge conflict.

[tytan652]

Conflict fixed.