Facility vehicles 002 fire_engine

Adds a smaller fire engine to accompany the large firetruck. 
Adds deluge guns as a deconstructible vehicle part. 
Makes the deluge gun a turret.
Fixes two deluge guns on the fire engine.
Makes fire engine spawn in some fire stations.

Justification: Didn't want to mess up the existing firetruck's layout by adding the guns and lots of water tanks, so put this one in.