Clear data on exit whitelist

Is your feature request related to a problem? Please describe. Although clearing data on exit is a good privacy practice, there are many websites that users can consider to be 'trustworthy'. For these websites it is often desired for user 'session' data to be preserved across discrete visits to trustworthy webites. A user defined whitelist of trustworthy sites, whose cookies and data are preserved upon exiting the browser would therefore be convenient for regularly accessed, trustworthy sites.

Describe the solution you'd like A UI element to be able to input/edit a user defined whitelist - A new section in the settings page would be more user friendly but probably more development work - A new flag entry in the flags page would be less friendly but probably easier to implement. A nice to have, would be a new menu item in context menus to add/remove current website to/from the whitelist. The whitelist would be input as a delimited list of URLs - for more control it would be nice to go beyond top level domain URLs and could include wildcards. Upon exiting the browser website data and cookies from URLs in the whitelist would be excluded from deletion when deleting data and cookies

Describe alternatives you've considered This behaviour can be achieved using existing plugins, such as Cookie Auto Delete, however for users who would prefer not to activate plugin functionality then there is no realistic alternative.

Additional context Add any other context or screenshots about the feature request here.