L2SS-1189: implemented a quick 'skeleton' for the L2Station & TMSS integration test. Useable for now, to be fully implemented in L2SS-1193

L2SS-1189: L2TMSSObservationControl (lobster) should only poll/pickup tmss observation subtasks with lofar2 stations only

L2SS-1190: added RPC to abort observation. Added ToDo-placeholder where the actual tango kill commands should be implemented

TMSS-2262: the Jira ticket says we need to check the specifications_doc for validity. That's superfluous cause TMSS already does that, but it doesn't hurt either.

TMSS-2262: wrote initial implementation for the Lofar2-TMSS observation controller. This controller listens to the lofar messagebus and acts on subtask event updates for quick handling, and polls at regular intervals for upcoming observations. Addded ToDo's for the specification conversion and station-spec-submission

(cherry picked from commit 9788c0a7)