[CI] Merge windows matrixes and include arm

[ssunday]

Closes #32

I don't have a windows machine so I can't test this, so we'll see how CI goes with the general changes + arm.

Windows arm image is from https://github.com/actions/partner-runner-images

[ssunday]

Well, the deps are building and can be tested https://github.com/OpenMW/openmw-deps-build/actions/runs/22074530698?pr=36. I can push an upload-deps fix, but probably someone should verify it even works before bothering.

[AnyOldName3]

I tried altering the before_script.msvc.sh so it could consume that build and attempt to cross-compile, but it's taken a lot longer than I'd hoped and I'm done fighting it for tonight (I've at least got it as far as CMake exploding, so the script is mostly fine).

[AnyOldName3]

It at least builds now. https://gitlab.com/AnyOldName3/openmw/-/commits/windows-arm64 is the branch with the necessary changes (and obviously it's a bodge that makes it able to consume the test build of the deps).

I don't know whether anything actually runs as I don't have the hardware, and Windows doesn't provide an emulation layer in the right direction. I can zip a build up if someone wants to give it a try.

[uramer]

I've tried running it on my Microsoft Surface and it works

[AnyOldName3]

One thing worth mentioning is that now we're cross-compiling, --export-all-installed is including a bunch of host triplet tools and libraries that I don't think we actually need even if we're cross-compiling. Now we're using a manifest, it should be easy to export only the things specified by the manifest instead of their build-time-only dependencies.

[ssunday]

Now we're using a manifest, it should be easy to export only the things specified by the manifest instead of their build-time-only dependencies. I'll make an issue for that, I feel like that deserves separate testing

[AnyOldName3]

It's already mentioned as part of #7, but cross-compiling has made the situation worse.