Iron mine and refinery added

Recently, I have been working on the Iron Mine and Iron Refinery (both the models and their backend logics). The Iron Mine can only be built on top of Iron Deposits and if there is at least one active mine with a deposit with resource more than 0, the refinery will be active and its transport drone will collect resources from the nearest mine. The drone movement will be only a visual thing as the actual resources are gathered after a wave is done.