Add _total suffix to counter metrics

Update metrics to match conventions expected by prometheus #86

@juliusv @jmyounker 
This and some others aren't really English plurals, although the meaning of the metric is. Maybe agree with the harpoonites on the best terms here, but some suggestions:

`container_create_total` -> `container_creates_total` or `container_create_events_total`
`container_destroy_total` -> analogous to above
`container_start_total` -> analogous to above
`container_stop_total` -> analogous to above

Not sure about how to do that best for these:
`container_status_kill_total`
`container_status_down_successful_total`
`container_status_force_down_successful_total`