Cameras can be broken by weapons/projectiles, fixes

Fixes being able to show papers to AIs through deactivated cameras.
Fixes being able to break doors with TOX, OXY, and CLONE damage.
Fixes camera alarms persisting after the camera is deleted.
Fixes #7021.
Some camera cleanup.
Fixes portable turret ex_act()

Class 3 is the least severe, not the most.
Merge remote-tracking branch 'upstream/dev' into camera

Conflicts:
	code/game/machinery/portable_turret.dm
Merge pull request #7215 from mwerezak/camera

Allows cameras to be broken