Add average for each flag and uptime to the fallback summary
When we generate a list of fallbacks, the script outputs a summary of the spread of IP blocks, ports, exit/non-exit, etc.
It would be useful to have the average flags and uptime in this list as well.
We could then do
success_without_auth = min(avg_uptime, avg_running, avg_v2dir)^3 and print it too.