chore: Port MPIHasher to Swift

[einsteinx2]

Summary

• Now that MPHasher C++ code has been refactored out and the MPIHasher Obj-C class updated, it was a prime candidate for a quick port to Swift as part of our ongoing porting efforts. This builds off of my previous PR here: https://github.com/mParticle/mparticle-apple-sdk/pull/233

  Testing Plan

• Confirmed that the hash functions produce the same output using our comprehensive unit tests

• Smoke tested with a local app

  Reference Issue (For mParticle employees only. Ignore if you are an outside contributor)

• Closes https://go.mparticle.com/work/SQDSDKS-5908

[einsteinx2]

After the other PR is merged, I will rebase this branch off of development, change the target branch for the PR to development, and switch to a real PR from a draft.