Import python module for notification in GGRC workflow initialization

This allows signals handlers to be kicked off immediately (instead of waiting for Deferred emails in 10 min)
Try `from ggrc_workflows.notification import notify_email_digest, notify_email_deferred` instead, to avoid importing the whole module.

Importing the module at all will trigger the Resource signal listening, which is what was missing before -- you don't need to import the whole thing.