Finish implementation of add/remove squadrons from AirWingConfigurationDialog

Users can now add and remove squadrons with specific buttons. this also allows new aircraft types to be added as well.

- rebased existing PR to develop
- reverted observable and changed to signals
- changed the general concept so that changes only affect the ui data model and not the game directly. Game will only be updated on apply
- removed unused code
- adopt to review comments
- allow user to choose a predefined squadron preset (also alow none value to use the random generator)
- Reuse the squadron defs from the default assigner in the AirWing class
- allow user to re-roll the squadron nickname (also added new ui icons for the button)

game/coalition.py

@@ -40,7 +40,7 @@ class Coalition:
         self.procurement_requests: OrderedSet[AircraftProcurementRequest] = OrderedSet()
         self.bullseye = Bullseye(Point(0, 0))
         self.faker = Faker(self.faction.locales)
-        self.air_wing = AirWing(player)
+        self.air_wing = AirWing(player, game, self.faction)
         self.transfers = PendingTransfers(game, player)
 
         # Late initialized because the two coalitions in the game are mutually