Draw frozen combat on the map.

Very basic display. Draws the engagement footprint for air-to-air
combat, a line from the flight to the target for IP, and lines from SAMs
to their target for air defense.

https://github.com/dcs-liberation/dcs_liberation/issues/1680

game/sim/gameupdatecallbacks.py

@@ -0,0 +1,17 @@
+from __future__ import annotations
+
+from collections.abc import Callable
+from dataclasses import dataclass
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from game.sim.combat import FrozenCombat
+
+
+# Ought to be frozen but mypy can't handle that:
+# https://github.com/python/mypy/issues/5485
+@dataclass
+class GameUpdateCallbacks:
+    on_simulation_complete: Callable[[], None]
+    on_add_combat: Callable[[FrozenCombat], None]
+    on_combat_changed: Callable[[FrozenCombat], None]