Added $auth_conf_entries parameter to init.pp

Custom auth.conf entries can now be specified through the $auth_conf_entries
parameter.
Reworked smart-proxy config file placement

The previous methodology of placing smart-proxy config files made it difficult
to write spec tests, and would have been confusing for new users to specify
overriding resources. The new way isn't pretty, but it's easier to
understand and much more forgiving.