Image Allow List user interface

[jandubois]

The user interface would be a separate tab on the "Container engine" page in the preferences.

The basic UI would look like this:

It can be augmented by an "image tester" to allow the user to check if a specific image name will match any of the defined patterns:

[jandubois]

Epics #3236 and #3237 cover the plan for the initial implementation