Filters miners by state miner power

Reduce noise in stats by filtering miners by state miner power similar to the approach in `boostx stats` [here](https://github.com/filecoin-project/boost/blob/main/cmd/boostx/stats_cmd.go#L61). This should reduce the total number of states a miner scanned by `heyfil` could be in and would produce statistics that are easier to digest by a human.