Fixes modkits

Fixes modkits not tracking suit/helmet parts, not checking allowed
parts, and not checking if the clothing needs to be modified.

(cherry picked from commit 789d3e4d54eb22ebc28536437cf7652f3ff6cd47)
Fixes skrell helmet refitting, modkit text

(cherry picked from commit e9772faabcff4eac867226084d884a777aa3b51d)