[Rewrite] Mining Systems

One major part of the Rewrite is that Mining needs to become an integral part of the gameplay. In order to keep me from reiterating a lot of stuff I've already written, refer to Concept: Mining Rewrite, but ignore all the "modification" stuff since we'd be rewriting this from the ground up, as per the whole point of Rewrite-All-The-Things.

A lot of work has already been done, as well, and can be ripped from the stale mining-rewrite/ branch.

Note: This is mainly a task announcement issue, since I plan on doing this bit. But I wouldn't mind help in getting spun up.