Task #8888: added OTDBBusListener which is a concrete implementation of the BusListener, listening to otdb status events and calling on<SomeEvent> methods

Task #8899: Credentials now have their own class, and a specific function to convert to str and to pg.connect options

Task #8899: Propagate username, password, port to pg.connect. Also, return dbcreds["port"] as an int

Task #8899: Updated OTDB services to accept and use dbcredentials; set exit code to 1 on invalid parameters

Task #8898: Write logfiles to CWD (allowing environment to go to $LOFARROOT, which cannot be used in stdxxx_logfile in supervisord < 3.2

Task #8531: Added checks to t_getTreeGroup to see if system can run test. Removed mimetypes from t_getTreeGroup.{run,sh}.

The fail_save administration of TreeStatusEvents program is now in the database.