cothority still depends on vgo

[jeffallen]

We decided that vgo wasn't ready for master, but it's still there:

cothority/conode/Makefile

Line 56 in 1a05ba9

vgo verify

This is reminder to finish removing it from here, go.mod* from repo root, and also vgo from inside of run_conode.sh.

[jeffallen]

When we are ready to try this again, we need to make sure that there's a fix for vgo needing to be logged into Github. That was a deal-breaker for us. See golang/go#23955