fixes #4463 - use unattended URL for hostgroup provisioning
refs #3260 - add label for default value tickbox to match overrides
fixes #7586, #7734, #7172 - user preferences for receiving mail notifications

Adds a framework for user-selectable mail notifications.  The work is
still done in ActionMailer classes and launch by rake in cron, however a
wrapper called MailNotification is used to provide RBAC and make the
association with users.

Plugins may seed their own mail notifications, see
db/seeds.d/16-mail-notifications.rb for an example.

Authors:
  Shlomi Zadok <szadok@redhat.com>
  Stephen Benjamin <stephen@redhat.com>
Fixes #8091: connect-src accepts WSS
Fixes #7954 - When creating a host cant is spelled wrong under partition table side note
refs #746 - hosts stylesheet is part of app.css, not standalone
Refs #969 - Foreman-side changes for serving templates from the proxy
Fixes #8258 - CR provider errors with correct log level
Fixes #7971 - DHCP hostname commutative conflict fix
Refs #3809 - fix shadowing outer local variables
fixes #6408 - dismiss org/loc context menu when mouse leaves it
Fixes #8285 - Update README.md
fixes #8277 - upgrade rails to 3.2.20
fixes #8302 - only return active images for openstack compute resources
Fixes #7462 - new UI for network interfaces
Fixes #7369 - External user groups update on login
Fixes #7456 - Extract primary interface from host

All host must have at least one primary interface and one provision (can
be the same interface). Primary interface gives host a name so even
unamanaged host have primary interface (we skip validations of other
attributes for unamanged hosts though).

Host still have name attribute which is a cache of primary interface name.
Therefore we can use the host name in SQL queries, as a friendly_id etc.
Fix functional tests
Fix more tests
Fix integration tests