[RFC] gitlab: add aports-qa-bot config
@developers This sets the configuration for aports-qa-bot, a new bot we have for automatically doing some tasks (e.g. checking the "Delete source branch when merge request is accepted." and "Allow commits from members who can merge to the target branch." checkboxes on MR creation in case contributors forget to set it). It also labels MRs which haven't seen any activity in the last 30 days as "status:mr-stale" and adds a comment to the MR (see
StaleMessage). See !10428 for an example of what the bot does. This decreases the amount of MRs which rot forever since either the contributor gets reminded about the MR or devs see it again because it gets to the top of the "last updated" queue in case it's blocked on a dev approving it. Would be nice if you could take a look at the StaleMessage and make sure it sounds OK to you.