Rocket turrets should aim at Destruction targets

[jb0lt]

Description of the feature

Rocket turrets should aim at the new Destruction target item and behave in the exact same way as Sentry turrets when presented with one.

Why should this be implemented

This would make sense because explosions can destroy the targets, although this feature should be togglable with a stylevar or something, as the way it currently is can also create some cool puzzles.

Additional information

The Rocket turret does not care in the slightest about the target (I turned on notarget for this screenshot)

[vrad-exe]

Rocket turrets only have the ability to search for one target at a time, for co-op I worked around that by using a npc_enemyfinder entity to switch targets dynamically - it should be possible to enable that logic in singleplayer and make it detect destruction targets too.