Support Linux aarch64

[martin-g]

Use sse2neon for translating SSE to NEON ops. Add CI based on Github Actions to verify that the project builds properly on x86_64 and aarch64

[martin-g]

The CI jobs will be activated for this repo when the workflow is pushed to the master branch, i.e. after merging this PR. Successful build could be seen at my fork: https://github.com/martin-g/wtdbg2/actions/runs/6309983436