cxx-qt-lib: Add support for QUuid

[jnbooth]

Adds a shared type for QUuid, which can optionally be converted to and from the type provided by the uuid crate. Since it's expensive to convert between Strings and QStrings, QUuids provide a convenient no-allocation alternative for identifiers.

[redstrate]

This looks pretty in-depth, thanks! I think this is definitely worthy of a mention in CHANGELOG.md, you should add it there in this PR.

I also started up the CI workflow, so we can see if that succeeds.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (1f72cdd) to head (ec120fe).
Report is 1 commits behind head on main.

Additional details and impacted files

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[LeonMatthesKDAB]

Hi @jnbooth ,
thank you for taking the time to work on this.
UUIDs are an important topic and having QUuid in cxx-qt-lib would be great!

I have left some minor nitpicks, but the most important problem is going to be Qt5 support, as QAnyStringView isn't supported on Qt5.
For now I'm okay to only support QString so we can merge this PR earlier.

[LeonMatthesKDAB]

Thank you for the contribution @jnbooth 🎉