Add a review approval for application limits

Problem

When an application limit is added, especially to the application_settings or plan_limits, the default value is not reviewed in full context.

Solution

The default value should be reviewed by the owner of that feature, likely a Product Manager.

This would take place during the review process, similar to a database, backend, or UX review. There could potentially be an Application Limits review, or another similar label.

The development docs for MR approval guidelines should add a section for this type of approval.