Fake structures use 'DamageThreshold' under 'Explodes'.

This change means that fake structures take damage at the same
rate as their real counterparts, but explode at 90% of their
max health.

MSLF and PDOF have been given a health buff as only one fake
version of each can be built.

Also fixed mission Monster Tank Madness. Actor v19.Husk required
HealthInfo.

mods/ra/rules/defaults.yaml

@@ -504,6 +504,9 @@
 	-GivesBuildableArea:
 	Health:
 		HP: 100
+	Explodes:
+		Weapon: Demolish
+		DamageThreshold: 90
 	RevealsShroud:
 		Range: 4c0
 	Fake: