The persisted view catalog per database is stored under <db>.system.views.

• The view catalog is split up across many persisted collections instead of stored in a single one
• This is separate from our regular catalog information in the __mdb_catalog

ViewGraphs are created per database rather than as part of a global ViewGraph

• A ViewGraph today can become invalidated and require reload (not sure how invalidation happens)
• We'd have to support more fine-grained reloads/invalidations, or stop supporting invalidation of the view graph.

It would probably be wise to consider how we're going to handle materialized views, eventually, so we move non-materialized view handling in a direction that can also supports materialized views eventually.