Ref T261, detect gnd.flag (from network) suppport, display gnd.flag info in UI

* add flag info in simulated aircraft
* allow to display info  in UI
* unified naming to "contains" in situation list
* updated client provider

src/blackmisc/simulation/simulatedaircraftlist.cpp

@@ -180,7 +180,7 @@ namespace BlackMisc
             for (CSimulatedAircraft &aircraft : (*this))
             {
                 if (aircraft.getCallsign() != callsign) { continue; }
-                aircraft.setSituation(situation);
+                aircraft.setSituation(situation); // also sets setSupportingGndFlag
                 if (onlyFirst) break;
             }
             return c;