Winterized Army Gear for military professions.

Because the loaded gun is the LAST thing they give to new soldiers. If we're
really going to have the game start in a snowstorm, even if it's for 'just a few days', then US Military
service members of all people shouldn't be scrambling for warmer
civilian clothes at the jump.

Adds winter_jacket_army, winter_pants_army, and winter_gloves_army to
armor.json and item_groups.json, as well as the three current military
professions in professions.json. Also gives all three military
professions balaclavas, gives recruits army helmets and helmet liners,
and bio soldiers berets.