Ability to destroy, capture, or loot enemy colonies

Basically, as the title says, we should be able to either destroy, loot or capture enemy system colonies. It's frustrating when you automatically take a system when you are at war with a faction and the action tips you over your colony limit. While you can evacuate the system, it seems unnecessary for it to be that complicated to avoid the negative Public Order . 

EDIT: Perhaps through the research of a technology there can be like "bomb the colony" after killing its defenders and what not. Maybe the Cravers can get a special like "strip colony" to take what they can use and burn the rest. Just more ideas.