Integrate censorship detector in Pyonionoo

The current censorship detector takes the output of metrics-web's daily direct usage numbers and tries to detect sudden drops or increases in usage. It would be good to also look at bridge usage for censorship events, and it would be quite important to have a tighter integration of the censorship detector into the usage-calculating process and look at raw numbers there. Right now, the vast majority of events that the censorship detector reports are just false positives. A tighter integration would also allow the censorship detector to process daily usage numbers as soon as there's enough certainty that they won't change significantly anymore, rather than waiting another two days until metrics-web is really sure numbers are final. Depends on #7154 (closed) where we'd first have to extend Pyonionoo to provide statistics on daily users.