Add the cache keys currently set in the graphical interface

[FaresAh]

As a user, I would like to be able to see in the graphical UI the keys currently set in Slimfaas' cache, with their associated TTL.

[guillaume-chervet]

Yeah, it would be a good idea for exemple to have a second tab in the actual web pages, where we can see the acutel cache keys and associated ttl with a button to be able to refresh the page (only on a clic).