Allow bandwidth scanners to use non-Exits to access onion addresses
Tor's bandwidth scanner passes the bandwidth server HTTPS address to Tor's SOCKSPort. So using an onion address should just work.
But to get the full benefit from onion addresses, we need to do two things:
- run the bandwidth server as a single onion service (otherwise the variance is too high), and
- allow the second relay in the path to be a middle or guard when connecting to onion addresses.