Eliminate Manta's movement

[AlyasGrey]

Alright, one of the biggest issues folks have with Manta is it's size.  The place is just way too small for antags, but beyond that the ship's movement and dangerous propellers render going outside a potential death sentence.

So, since we can't seem to agree on removing Manta from the rotation, how about we disable it's movement at the very least?  No other map suffers from the same problem and every single one of the other common maps is already more suitable for indoor antag stuff.