Separate configuration step from building step

[trustytrojan]

Please separate the CMake configure and build steps when running the Catnip tool.

It's kind of annoying to have to delete my entire build folder just to reconfigure because I adjusted my source tree. I would prefer if the CLI behaved more like CMake itself, where I run catnip -T nds to ONLY configure, and then catnip build to actually build.

[fincs]

A command to only perform CMake configuration is planned to be added.