Provide guidance for M1 Mac installations

Requested by @jackaraz , can we add a section on Mac M1/M2 build "strategy" to get a functioning Rivet from tarball / bootstrap? This needs input from those running on those platforms, either via Rosetta (Jon) or natively (Chris?). A lot of the support requests we are now getting are from folk with very bespoke/layered environments such as Mac+Homebrew+Conda+venv, so hopefully having a standard route to successful installation will give us an easy thing to point them at. Thanks!