Add Mac Catalyst build and TestFlight upload in CI

[mokagio]

What is says in the title :)

I manually started a build to test this, so there's no surprises once merging.

Here's screenshot of the CI logs, notice the build number: 9

I'm aware of the warnings. They are due to the env or build folder containing both ipa and pkg after having built them in the same job.

and here's screenshots of the matching build on TestFlight, on both platforms:

[ellatrix]

Thanks so much @mokagio!