Maybe monitoring values in the state file should be reset when sbws is restarted

I think the following keys should probably be restarted, to make less confusing what appears in the bandwidth file. For instance, after restarting longclaw's sbws, this is what the state file contains, consensus count and priority lists are reset, but not the others:

    "recent_measurement_attempt_count": 671,
    "recent_consensus_count": 1,
    "recent_priority_relay_count": 984,
    "recent_priority_list_count": 3,
    "min_perc_reached": "2019-05-06T06:20:49",