Add a Boss to Level 10

[nvs]

I'm not entirely sure how easily I can add this in as an extra monster (this would probably be error prone, as lots of checks in the code expect 10 kills). It may have to replace one of the existing ones. Not a big deal, but the only real issue outside of not making it too difficult (or easy).

[nvs]

Going to wait on this on, for now. There are not enough early game options or mechanics to really create an interesting boss this early into the game.

[GaDaHo]

Make it for fun then!