YAML and minor refactoring

This PR changes the way global and user settings are used. A YAML configuration file is now utilized over the db.py and auth_user settings. All settings are server-side only so this doesn't change functionality in any way.

Kvasir will look for a 'kvasir.yaml' file in $HOME/.kvasir/ first followed by $WEB2PY_HOME/applications/$APPNAME/

This PR also includes a move of host-based skaldship functions into skaldship/host.py