Continue squad qol

[OH296]

• makes tweaks to squad garrison mechanics
• added some qol and polish to the squad ui
• adds black carpapace/removes carpace from scouts on spawn(except space wolves)
• scouts now have slightly lower start stats
• every 15exp now adds a random stat point in either wepaon_skill,ballistic_skill or wisdom
• at the end of battles give a total of how many exp points were gained so players know dudes are actually getting exp
• fix apothecary healing of unit's on the ground at turn end
• integrate more repeated functionality into statics in the unit struct (e.g gaining exp and unloading ships, healing)