Opt-out registration on the " Organization Address and Contact Info" screen

Add an opt-out registration to this page:

• at the end of the form, add a few fields that mirror the 'Register a site form', including Number of Employees (we should probably use 'staff' here), Annual Budget, Organization Category and Publish your Responses.
• above the 'Save' button, create a check-box (checked by default) that states "Register my site with CiviCRM.org. This information is necessary as part of the grants we receive and in order to better understand our user base when planning for new features."
• On the Save action, if the check-box is checked, proceed with a site registration on the CiviCRM.org website. We might run into issues with the XSS token, but I trust CiviCRM to deal with duplicates/multiple submissions in a sound way.