[Dbix-class] Database handling refactored (mostly) into Storage::DBI

[Matt S Trout]

I've created a separate ::Storage::DBI module that handles the interaction
with the database (except for the compat layer which calls back in to get
the dbh et. al.).

DB.pm is now a nice simple way to set this up on a per-class basis; see
perldoc DBIx::Class::DB for a short explanation.

-- 
     Matt S Trout           Website: http://www.shadowcatsystems.co.uk
  Technical Director        E-mail:  mst (at) shadowcatsystems.co.uk
Shadowcat Systems Ltd.