Improve AI strike targeting.

We were setting up all the correct *target* waypoints but the AI doesn't
use the target waypoints; they use the targets property of the ingress
waypoint. This meant that the flight plan looked correct in the UI and
was correct for players but the tasks were set up incorrectly for the AI
because building TGOs are aggravatingly multiple TGOs with the same name
in the implementation.

Mission targets now enumerate their own strike targets so that this
mistake is harder to make in the future.

This won't be perfect, the AI is still not able to parallelize tasks and
since buildings aren't groups they can only attack one structure at a
time, but they'll now at least switch to the next target after hitting
the first one.

As a bonus, stop bombing the dead buildings.

Fixes https://github.com/dcs-liberation/dcs_liberation/issues/235
Fixes https://github.com/dcs-liberation/dcs_liberation/issues/244

gen/flights/flight.py

@@ -2,10 +2,11 @@ from __future__ import annotations
 
 from datetime import timedelta
 from enum import Enum
-from typing import List, Optional, TYPE_CHECKING, Type
+from typing import List, Optional, TYPE_CHECKING, Type, Union
 
 from dcs.mapping import Point
 from dcs.point import MovingPoint, PointAction
+from dcs.unit import Unit
 from dcs.unittype import FlyingType
 
 from game import db
@@ -107,7 +108,7 @@ class FlightWaypoint:
         # Only used in the waypoint list in the flight edit page. No sense
         # having three names. A short and long form is enough.
         self.description = ""
-        self.targets: List[MissionTarget] = []
+        self.targets: List[Union[MissionTarget, Unit]] = []
         self.obj_name = ""
         self.pretty_name = ""
         self.only_for_player = False

gen/flights/waypointbuilder.py

@@ -202,8 +202,7 @@ class WaypointBuilder:
         waypoint.pretty_name = "INGRESS on " + objective.name
         waypoint.description = "INGRESS on " + objective.name
         waypoint.name = "INGRESS"
-        # TODO: This seems wrong, but it's what was there before.
-        waypoint.targets.append(objective)
+        waypoint.targets = objective.strike_targets
         return waypoint
 
     def egress(self, position: Point, target: MissionTarget) -> FlightWaypoint: