Add start scripts for checker and rule manager

[aracho1]

What does this change?

Add start scripts for:

• The rule manager (script/start-manager)
• The checker (script/start-checker)
• both together (script/start).

How to test

Running each script from the project root should start the respective service, with (--debug flag) or without the debugger.

How can we measure success?

Devs can start the whole app or each service more easily.

Have we considered potential risks?

Tested locally.

[ParisaTork]

Great to see this change - a couple of comments

[aracho1]

Thanks for the review @phillipbarron @ParisaTork!