Fix time travel over Iceberg materialized views

[tdcmeehan]

#26616 added support for basic materialized views, however time travel doesn't work. In order for time travel to work properly, we need to translate the version specified during the query on the materialized view to the base tables and to the data table.

If a VERSION is used, then we need to look up the version of the view specified, and determine the snapshot IDs of the base tables and data table for that version.
If a TIMESTAMP is used, then we simply need to propogate the timestamp to the base table and data tables (or, perhaps, look up the VERSION corresponding to the TIMESTAMP, and do the above technique).