Implement the call to list all databases in a store

So far:

mod = :barrel_store_provider.get_provider_module(:default)

:barrel_memory_storage

iex(13)> :barrel_memory_storage.list_barrels(:default)

** (FunctionClauseError) no function clause matching in :barrel_memory_storage.list_barrels/1

to sum up :barrel_memory_storage.list_barrels/1 is temporarily failing ajnd I'll need to implement this command later on. Also. check whether there will be multiple stores (Database.all(store)) or one (Database.all)