gerrit-autosubmit: put all config in one place

#334
Opened by tazjin at 2023-11-27T21·49+00

Review comment from flokli on cl/10131:

Can this be GERRIT_PASSWORD_FILE? That'll allow keeping all of the config visible, and the password to not live in the env

For now I used the config structure of gerrit-queue so that we could just reuse the secret etc., in principle we can change it later (just requires redoing the secret etc. and I don't want to deal with it right now).