Suggestion: Adding a 'machine' argument to ./run_tower

Hi

I have been using ./run_tower (https://github.com/ESCOMP/CTSM/blob/master/tools/site_and_regional/run_tower) for a couple of months, and it is a fantastic tool; however, it would be great to include a 'machine'argument, same as create_case, to work on different machines.

This is an idea of how the suggestion could look:

./run_tower --plumber-site AT-Neu .... --machine izumi

Thank you in advance for considering this enhancement issue