Add an option for default start type.

Changing this completely breaks OCA/Aircraft missions, but if the player
doesn't care about those this can reduce airfield congestion. The UI
warns about this.

This also makes the AI start type selectable in the flight UI.

Fixes https://github.com/Khopa/dcs_liberation/issues/387
Fixes https://github.com/Khopa/dcs_liberation/issues/729

gen/flights/ai_flight_planner.py

@@ -563,15 +563,22 @@ class CoalitionMissionPlanner:
             ])
 
         for target in self.objective_finder.oca_targets(min_aircraft=20):
-            yield ProposedMission(target, [
-                ProposedFlight(FlightType.OCA_AIRCRAFT, 2, self.MAX_OCA_RANGE),
+            flights = [
                 ProposedFlight(FlightType.OCA_RUNWAY, 2, self.MAX_OCA_RANGE),
+            ]
+            if self.game.settings.default_start_type == "Cold":
+                # Only schedule if the default start type is Cold. If the player
+                # has set anything else there are no targets to hit.
+                flights.append(ProposedFlight(FlightType.OCA_AIRCRAFT, 2,
+                                              self.MAX_OCA_RANGE))
+            flights.extend([
                 # TODO: Max escort range.
                 ProposedFlight(FlightType.ESCORT, 2, self.MAX_OCA_RANGE,
                                EscortType.AirToAir),
                 ProposedFlight(FlightType.SEAD, 2, self.MAX_OCA_RANGE,
                                EscortType.Sead),
             ])
+            yield ProposedMission(target, flights)
 
         # Plan strike missions.
         for target in self.objective_finder.strike_targets():
@@ -651,11 +658,6 @@ class CoalitionMissionPlanner:
                      reserves: bool = False) -> None:
         """Allocates aircraft for a proposed mission and adds it to the ATO."""
 
-        if self.game.settings.perf_ai_parking_start:
-            start_type = "Cold"
-        else:
-            start_type = "Warm"
-
         if self.is_player:
             package_country = self.game.player_country
         else:
@@ -667,7 +669,7 @@ class CoalitionMissionPlanner:
             self.game.aircraft_inventory,
             self.is_player,
             package_country,
-            start_type
+            self.game.settings.default_start_type
         )
 
         # Attempt to plan all the main elements of the mission first. Escorts