ore generator

name: 洞天（暂定）

a function of get the ore/block/others. since the ore generator is not very common, we could make it a bit more complex. Same as the furnace, we can still make it has the difference with difference usage.

first level is stone generator/water/lava, then the ore with slow speed, then the ore with high speed.

need to maintain the user's function less.

let user use dfs to solve labyrinth to get ore.