[PR] `/obj/item/assembly`-Rework

[Lord_earthfire]

There is quite a bit mire than QoL innthat rework. There are new assembly types and some changes in behaviour. E.g. borg arms can be attached onto timers and when activated throw pies at the nearest person in a radius. Singletank bombs can be placed unto mousetrap rollers. Or bike horns onto proximity sensors.