[ast / otp] Consider tying specific read / write lock to dev mode

To prevent specific proprietary pieces from being explored in DEV mode (thus preventing wider distribution of DEV mode parts at the moment), we should enhance `ast` and `otp` to lock out specific pieces even during DEV mode.

This would include ast register read / write lock and also a specific software partition inside otp.

These would be fairly big changes on `otp` right now, so we might not be able to entertain this for the upcoming milestones.