Point in time key recovery

[nimish-ks]

Allow apps keys to be recovered once an app has been deleted.

[rohan-chaturvedi]

Some questions about this:

• Should this feature be opt-in or opt-out?
• Would a deleted app be referenced by the APP_ID , backend uuid or name?
• Would retrieving keys for a deleted app mean restoring the app in the console, with logs etc?
• Should there be a way to permanently delete app keys?