Retreat ground forces from captured bases.

If the captured base has no connection to other friendly objectives (the
base was encircled) then the enemy equipment will be captured and sold.
Otherwise the units will retreat toward connected bases.

Partial fix for https://github.com/Khopa/dcs_liberation/issues/693.
Still need to fix this for air units.

game/theater/base.py

@@ -9,6 +9,7 @@ from dcs.unittype import FlyingType, UnitType, VehicleType
 from dcs.vehicles import AirDefence, Armor
 
 from game import db
+from game.db import PRICES
 from gen.ground_forces.ai_ground_planner_db import TYPE_SHORAD
 
 STRENGTH_AA_ASSEMBLE_MIN = 0.2
@@ -37,6 +38,16 @@ class Base:
     def total_armor(self) -> int:
         return sum(self.armor.values())
 
+    @property
+    def total_armor_value(self) -> int:
+        total = 0
+        for unit_type, count in self.armor.items():
+            try:
+                total += PRICES[unit_type] * count
+            except KeyError:
+                logging.exception(f"No price found for {unit_type.id}")
+        return total
+
     @property
     def total_frontline_aa(self) -> int:
         return sum([v for k, v in self.armor.items() if k in TYPE_SHORAD])