Move organization support from UserAccount to User model.

Previously we required an account to associate a user to an organization.
Support unified remote user directory search

Support searching both staff and user backends via a common interface.
Add users to organization

Support adding existing or new users while on organization page.
validation: Fixup a few email address validations
orgs: Add UI support to configure contacts and collaboration
orgs: Auto import based on email domain
orgs: Auto assign tickets to account manager
orgs: Auto add collaborators to new tickets
orgs: Add alerts for account manager
Always notify managers on new ticket