Manage two schemas by different MBD dists

This puts the contents of db into the dist's share directory.  This adds a dep on File::ShareDir, but it is a relatively light dep and a useful one.  Updated the documentation to reflect this (the old documentation documented a feature that wasn't actually implemented).

Also when dealing with patches_applied make sure we are working with that table from the target schema and not picking it up from another schema.

This allows having two schemas in one database to be manged by two different MBD dists.  I added an example that I used during testing.