Replace Burner miner/inserter with a simpler generator

[Prezombie]

Once you pass the tutorial, the burner inserter is completely pointless. It would make more sense to make a backup generator unit which would do all the burning for the slow inserter and the small miner.

The portable generator could act like a substation with a smaller aura, giving it a long-term viability once you start building your electric network.

The Small Miner would also have long-term uses, by being placed on the occasional outlier source tile you wouldn't have to waste a 3x3 miner.

As for the slow inserter, it would also have its uses once electrified, simply by being unable to pick up an item on a belt if it goes past, but able to pick up items if the lane backs up to the watched tile.