gerrit: Figure out Autosubmit feature

Opened by tazjin at 2021-02-21T18·53+00

In Another Code Review Tool (tm), there is a feature for letting change owners decide whether the reviewers are allowed to submit their change (fire & forget style reviews).

It would be useful to have an equivalent feature in our Gerrit. Apparently, the Android Gerrit instance has a feature for this that is implemented using a bot - that might not be too difficult to do, but it would be nice if there was a way of doing it that didn't fully require us to implement it.