remove cloak field generators from surplus crate

[Berrik]

These are never useful unless you're a traitor mechanic anyways.

[Frank_Stein]

Maybe cloak fields should come with some kind of goggles or glasses that let you see normally when they are active?

[Dabir]

Surplus crates are meant to be a gamble. Figure out how to work with them if you get them.

[Marquesas]

This is a bad idea.