If you came here thinking this was some game feature then you are in the wrong place. Here is where I ramble about code.
This adds /datum/element as a sort of sibling to components. Only one of each type gets instanced and they do not get tied directly to any particular thing like a component does. Basically they're a very lightweight component for doing simple functionality that doesn't have much state.
Originally this concept came about as a kind of component that could be shared between many parents to reduce some resource costs. Doing this would allow us to componentize more behaviors that are a part of too many things to be viable to have a whole component for every single one. For example a component on every space turf would be entirely unviable. With elements it's much more reasonable.
This implements a prety bare framework and a couple components are migrated to it. It's ready to be used but I fully expect I'm going to need to refine how it works for all the usecases we'll want it for.
Also: this fixes the qdeleted signal. This signal isn't even possible because after qdel is done there's nothing to receive a signal anyway. I've changed it to a qdeling signal instead. I need it to work for some elements to know when to clean themselves up.
