database: remove unused PatternQuery
Created by: keegancsmith
This was functionality I added a few years ago in pursuit of and/or search queries. There was code which transformed a hierarchical search query into WHERE clause against the repos table to help limit scope.
The idea of this package was to further extend it to create a more expressive and less clunky alternative to the growing ReposListOptions struct. However, the code has just remained unused so lets remove it. Maybe someone will like this idea and pick it up again.