Self-service VCS verification should verify io domains, not net

[tobias]

Our docs and the manual verification process verified com.github.org and io.github.org, but the self-service system verifies com.github.org and net.github.org, which is incorrect.

We should instead verify the io groups, and backfill io for anyone that has net.

This should also be fixed for gitlab.

[tobias]

This was fixed by #865 and all net.github group verifications now have a corresponding io.github verification. We had no net.gitlab verifications.