Use ObjectID as time/date for MongoDB

Feature request
In MongoDB the ObjectID contains a timestamp. This timestamp defaults to the time the ObjectID was created and thus is a very good way to keep track of creation date without adding another field.

Unfortunately, Metabase considers this field to be strictly an id, and thus can't group, select nor display the field as a date (i.e. group by month, select later than date X and show it as a human readable date).

The issue names no files, tests, or entry points. Start by locating MongoDB field handling in Metabase and trace how fields are typed, grouped, filtered, and displayed; the work is done when an ObjectID timestamp can be treated as a human-readable date for those operations.

Written by the indexing model from the issue text.