Procedurally generated mob spawn

[tacotexmex]

Read https://github.com/oilboi/Crafter/commit/6482ca1a7810591cfa7cccaba6ac1a3d1dd9946f and thought that finding spawn points procedurally based on world seed would be more interesting than a randomized timer.

I realize this departs from the MC way of doing it, so just close if not relevant.

[oilboi]

It can be both