CDK-633: Update hive uris

Previously, all datasets were created with no Kite namespace and the default Hive database. Now, some path parts in the URI are interpreted as namespace so it might appear that there is a namespace, but it is just the containing folder that we used to consider the repository root. In that case, we just check to see if there is a default table with the same name and that it's location matches (for external) or that it is managed.