Serialize pixelmap/material/model/actor structs to file

[madebr]

This pr add support for serializing pixelmaps, materials, models and actors:
the functions BrXXXSave and BrXXXSaveAll now have a (working) implementation.

To get there, this pr does:

• implement all regsupt methods: it is now possible to enumerate/find/add/remove tables/maps/materials/models from the central registry
• fix tests to handle with polluted brender state (=state where the register might not be empty)
• fix the temporary folder/file logic in the tests to be more stable (=added tests)
• Add a stub implementation for BrPixelmapDirectLock and BrPixelmapDirectUnlock.
• Implement + test all vector functions, because I used some of these in the tests.
• Add a BRENDER_FIX_BUGS cmake option to fix brender oversights. The tests will fail when not defining it.
• Implement all brstddiag functions. The message passed toBrFailure will be printed to stdout.
• Use BRender types in brstdfile.c
• (Completely) implement v1dbfile + pmfile: serializing pixelmaps, materials, models and actors now work. I've added the chunk ids + stack ids to separate headers.
• Fix test_loading_ConvertPixToStripMap on Linux. There was an issue with casings.
• Fix the tests to work on Windows due to differences in endlines (\r\n vs \n).

Result of running github actions on my fork: https://github.com/madebr/dethrace/actions/runs/1778285699

[dethrace-labs]

Can we not use the offsetof(br_face, vertices[1]) notation here?

[madebr]

Yes we can. I will add a commit.

[dethrace-labs]

where does the wrapping to BR_SCALAR(f1) come from? Is it necessary? Are you interested in adding support for running brender in fixed mode?

[madebr]

The wrapping comes from MATH/fixed.h.
It's not necessary, but I added it here to make it clear that a scalar is expected, not an explicit float/fixed.

I'm not that interested in getting fixed support working.
Getting dethrace working on current machines is a task big enough.

But I'd like to get our brender implementation sufficiently compatible with the brender used by carmageddon.
I would like to use our brender to link to the brender drivers and get good compatibility.