Support "catch-all" endpoints

[aler9]

Currently, messages are routed to endpoints and nodes only when message system ID and component ID match the node one.

It would be useful to have some endpoints to which messages are routed regardless of system ID and component ID, for logging or sniffing purposes.

[thezenox]

I needed the same thing and solved it like this Neomium@910ed3b
as its more a hacky hardcoded solution than a sustainable one, I would refrain from making a pull request.

EDIT: Fixed