Enable admins to delete configuration subsections

We need to add the ability to remove configuration subsections (locking, expiration etc) and make it consistent across configuration screens.

UI perspective: We could have a delete icon (red cross or trash can etc) in the "panel-title" div of the section that a user is editing. If the user chooses to delete this sections config, then they should be presented with a message screen saying "<section> has not been defined, would you like to define this now?" similar to how we ask users to define container security when they click on the security section. Similarly, if a user loads an existing config with a section undefined, the aforementioned message should be displayed.