Description of problem:
Some Zanata servers may be set up with a single authentication provider that is trusted to provide valid email addresses. It should be possible to configure a Zanata server to use email addresses from a trusted provider without a validation step.
For example, an OpenID provider may be used which always provides an email address that it has already validated.
We really should start looking at OAuth too. I think Phabricators implementation of this is a good one to go off.
Migrated; check JIRA for bug status: http://zanata.atlassian.net/browse/ZNTA-290