Meson: RoboRIO Toolchain Selection

[mfisher31]

This could be done with with meson_options.txt to choose the path (or even just be auto detection if a flag is set) to the installed location. Meson has the ability to configure a cross build by using a *.cmake configuration. Thankfully, installing WPIlib provides this + the toolchain itself. This is step one in deploying native LuaJIT to the rio... compile for it. A little work might be needed to also set up include and linker paths.

Specify cmake config in a meson.build
robotpy/mostrobotpy#33 (comment)

As an extra added bonus, doing this gives us a re-usable framework to skip using gradle all together.