Migrate CI to github actions

[clintfred]

A good starting point is what we are doing for gridiron. https://github.com/IronCoreLabs/gridiron/actions/runs/83301015
AC:

• show Linux, OSX, Windows, Android, iOS comparability
• run tests and benches on at least some architectures

On Travis we run the before/after benchmarks on Linux. There is value there, but sometimes because the machine is shared the results can give false positives. Probably shouldn't be handled here, but we could run the benches on some dedicated machine somewhere as that's something GA supports.

Open questions:

• should we build with and without the wasm feature?
• what targets do we want to run tests on?