Move workflows to own module

The workflows currently used in some of the functions in repod.cli.cli need to be moved to their own module (i.e. repod.action.workflow). The function calls need to be made explicit and their signature be changed to require all parameters used as part of a given workflow (instead of only relying on Namespace which may or may not provide what we need).

Decoupling will be very beneficial for future use of the workflows in different contexts (e.g. API).