Add GitHub action for macOS builds

[stweil]

No description provided.

[stweil]

This pull request depends on pull request #410 and currently ignores errors from make check because of issue OCR-D/ocrd_froc#10.

It must be triggered manually, but could also be run for example weekly in the future to detect any regressions earlier.

[stweil]

I tried two different variants for getting the submodules:

1. action/checkout can get all submodules recursively. By default it uses depth 1, but as it gets more submodules than required, it takes 189 s for the checkout step.
2. Get submodules during the build process (make all GIT_DEPTH="--depth 1"). That costs about 45 s during the build step, but reduces the time for the checkout step to 1 s.

So the. 2nd variant is much better, at least with GIT_DEPTH="--depth 1" which should be used by all CI and Docker builds. Currently those builds don't use it.

[stweil]

Example result for this action: https://github.com/stweil/ocrd_all/actions/runs/8294000625/job/22698144574.

[bertsky]

Suggested change

	run: make check || echo "make check failed"
	run: make check

[stweil]

Done. Note that the check will now fail until ocrd_froc was updated.

[bertsky]

Suggested change

- '3.7'

[stweil]

Done, thank you for your review.