Important changes for service filtering

Some important changes for service filtering to support resources:
* Support the notion of ANY service_type in the service filter for
  user preferences.
* Create a join method in ServiceFilter to join a resource
  filter with a user preference.
* Support service filter preference in session.

For example if a user wanted to use region='East' they would create
a service filter preference in their session with that region and
use that session with any resource.

Change-Id: I13fc2838b66ec85bdd0191c78b27b3cd685a8322
Merge "Important changes for service filtering"