Add config files to Bluehawk

[krollins-mdb]

Closes #122

This PR adds the ability to define and orchestrate Bluehawk commands using YAML config files. While I was in there, I also took the opportunity to make the terminal messages easier to parse. This was necessary, as it could quickly become unclear which command came from which config file if there are more than one config file.

Potential issue:

• I really wasn't sure how to write tests for this. Existing tests all pass locally. I tested the functionality using a test app that has config files. Should I create a mock test app in the Bluehawk repo so that we can test against that?