Add "format:" to the tile and entity cards

[mbo18]

It would be nice to be able to change the format for timestamp sensors for the tile and the entity cards like we are able to do it for the entities card.

I currently mix tile cards and an entity card but it not nice

What’s fun is that there’s no error when using format with the tile card even if not supported:

Just noticed that it changed following this issue: #14380
I'm wondering why it has been changed without having been made configurable.