Add performance option to not cull threatening IADS (#1953)

- Don't cull EWRs in detection range.
- Don't cull SAMs within threat range + small buffer.

game/settings/settings.py

@@ -450,6 +450,12 @@ class Settings:
         max=10000,
         causes_expensive_game_update=True,
     )
+    perf_do_not_cull_threatening_iads: bool = boolean_option(
+        "Do not cull threatening IADS",
+        page=MISSION_GENERATOR_PAGE,
+        section=PERFORMANCE_SECTION,
+        default=True,
+    )
     perf_do_not_cull_carrier: bool = boolean_option(
         "Do not cull carrier's surroundings",
         page=MISSION_GENERATOR_PAGE,