Schemas and Databases search through the query engine

[DanCodedThis]

Partial #522

• Changed list handlers for schemas and databases
• Fixed tests
• Added created_at, updated_at to the volume view and database view
• Decided to stop since the pr is already long enough
• And because right now metastore returns more info in list tables and list volumes
• For tables it's understandable that we need to add total-files-size and total-records to the view
• For volumes it's not so simple (we don't use the handler yet) we need to understand the scope of what we want to return in the view, right now it seems to return even credentials and a lot of info which, if considering different types won't be possible to put in the view (and we shouldn't)

[YaroslavLitvinov]

I would wait before merging this before getting additional approval, some things looks controversial and better to be fixed