REFACTORED CoreSchema model to play nicer with Model::DBIC

The CoreSchema model now conforms better to the intended API provided by
Catalyst::Model::DBIC::Schema. It no longer tries to override Moose
attrs; instead it now hooks into before 'COMPONENT' and uses the
standard config system. And, the auto deploy now happens in the same
order as normal connect, instead of trying to one-off
use/connect/deploy, since this could cause "Inconsistent hierarchy
during C3 merge" exceptions in certain scenarios. The new structure
should be safe/clean/dependable going forward...

Also, the user app is now able to override any of the configs by using
the 'Model::RapidApp::CoreSchema' config key, including a special
'sqlite_file' key (which defaults to 'rapidapp_coreschema.db' (which is
relative to the app home dir), as well as the standard 'schema_class'
and 'connect_info' keys.