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