API-only flag on Collections and Fields

System collections and their default fields prohibits changes by Users. New fields can be added to capture additional information, e.g. tags, without affecting its core functionalities.

It would be nice to have the similar preventative mechanism applied to application-core schema. As title suggested, an api_only attribute can be added to collection and field meta. This field is rendered as read-only in the App.

If it is set on a collection, no changes to the collection and its fields can be made via the App UI. This would supersed the field-level attribute of the same collection.

If it is set on a field, no changes can be made to the field and its collection is protected from being deleted. New fields can still be added/updated/deleted for this collection.

This is a useful feature to prevent admin mistakes from breaking integration with the front-end and other (micro) services.