Moat bucket shouldn't have non-obfs4/vanilla bridges

While doing some data visualization for tpo/network-health/team#115 (comment 2750865), I noticed that we have more than 200 bridges without any pluggable transport enabled on Moat bucket. Talking with Richard, it looks like Tor Browser only requests obfs4 bridges using Moat. So, these bridges aren't being used at all.

We could reallocate these vanilla bridges on another bucket and move more obfs4 bridges from other buckets to Moat, as this is the most popular way to fetch Tor bridges.

moat-bucket-non-obfs4-bridges_2021-09-23T21_50_49.71273-03_00.csv