11815 installer

Run install via web browser
The step "Install example content" should now be "Additional options"
The step should have a form to allow the user to register. The register form should display after checking "Register aGov"
At the moment, the only required value is a valid email address.
After install, and login as admin, visit /admin/register - If previous registration was completed, message and information should be displayed and allow the user to update.
If a registration cant be completed at the time of posting, it should be stored and retried via cron