Add tensorflow-macos conda package

[eberrigan]

Summary

• Currently, tensorflow-macos is pip-installed in SLEAP.
• This approach results in the SLEAP conda package for macOS being very large.
• We already maintain a tensorflow conda package for Windows/Linux.
• We propose to maintain a tensorflow-macos conda package for SLEAP to use when building the SLEAP conda package or creating a SLEAP development environment on Apple silicon macs.
• All SLEAP conda packages (for different OS') will then be similarly sized.
• Maintaining tensorflow conda packages separately from the SLEAP conda packages adds flexibility to our builds.

Implementation

1. Create tensorflow-macos Conda Package:

   • Using `tensorflow-macos == 2.9.2 and Python 3.10.
   • Figure out dependencies.
   • Make meta.yaml and build.sh.

2. Test tensorflow-macos Conda Package

   • Download package.
   • Create environment with package.
   • Make sure tensorflow-macos can be imported and find local GPUs.

3. Update SLEAP Conda Build:

   • Modify the SLEAP conda build process to use the new tensorflow-macos conda package when building on Apple silicon macs.
   • Test with CI.