Feature Request: Allow control over automatic build creation on commit

It would be nice to have some level of control over when CI builds get automatically created. In my instance, I would prefer to do nightly builds instead of per-commit. I have some projects where build/test can take a long time, so it's better from a loading perspective to batch up the CI to occur once per day.

It's easy to trigger a nightly build using the triggers API, but there's no straightforward way to disable automatic builds. The only mechanism I see is to add [ci skip] to each commit message, but that would clutter up our commit log and is error-prone; it would be undesirable to start a build if a developer forgot the tag.

#12947 (closed) also talks about adding some controls over which users would auto-trigger builds; that could perhaps be used to address this issue as well (by just disabling the auto-trigger behavior for all users).