Default new users to be "watchers" of an issue tracker

I had a discussion with a GitLab user from MIT who asked for the ability to have new users automatically set as "watchers" for a given issue tracker. From our discussion notes:

We create lots of users. We live on issue trackers for messaging. When we create a new user, we want them to watch an issue tracker by default.

Right now, the best solution we've provided is to use the UI or the API to impersonate the user and set them to watch the issue tracker.

This ticket is to track the ask for a way to configure GitLab so that new users by default watch the issue tracker.