Unify configuration option names
Reorder rpisps module components
Create base class for Requests/ServicesThread
controller.py: Implement can_pass_to_router/other

The methods `can_pass_to_router' and `can_pass_to_other' from
`ServicesRequestsBaseThread' get, in the derived classes
`ServicesThread' and `RequestsThread', bound to the names
`can_handle_reply', `can_handle_request' respectively.