xenia-build:
Make release the default config. (no longer need --config=Release)
Add --cpu_arch argument;
Valid options are SSE2 (default), AVX, AVX2, and AVX512.
CI:
Remove unneeded env vars since we're only building Release for Windows anyway.
Only do tests on AppVeyor since they only work there.
AppVeyor:
Remove empty tab/space.
Remove unneeded cmds.
Turn deploy off since it didn't do anything.
GitHub Actions:
Rename GitHub Actions artifacts.
Premake:
Remove commented out garbage.