Add cross compilers for robot firmware building on MacOS

[nycrat]

Description

Important

Running ./environment_setup/setup_software_mac.sh is necessary for these changes to take effect

This PR implements support for the following features:

• Building motor firmware (fix stm32 cross compiler installation)
• Building thunderloop and powerloop (install cross compiler https://github.com/messense/homebrew-macos-cross-toolchains)
• Flashing thunderloop, motors, powerboard

Testing Done

• Flashed robot software (thunderloop)
• Flashed motor board firmware
• Flashed power board firmware

Resolved Issues

Not an issue but look at the todo list from #3496 which includes cross compilation

Length Justification and Key Files to Review

Review Checklist

It is the reviewers responsibility to also make sure every item here has been covered

• Function & Class comments: All function definitions (usually in the .h file) should have a javadoc style comment at the start of them. For examples, see the functions defined in thunderbots/software/geom. Similarly, all classes should have an associated Javadoc comment explaining the purpose of the class.
• Remove all commented out code
• Remove extra print statements: for example, those just used for testing
• Resolve all TODO's: All TODO (or similar) statements should either be completed or associated with a github issue