Presently this is called in [[RegisterCgiScript]] directly after a call to verify. The separation is intended for the [[RegistrationApprovals]] functionality
1. calls \_reloadUserContext (throws oops if appropriate)
-2. calls newUserFromTemplate()
+2. calls createUserTopic()
3. if using the htpasswdFormatFamily, calls \_addUserToPasswordSystem
4. calls the misnamed [[RegistrationHandler]] to set cookies
-5. calls addUserToTWikiUsersTopic
+5. calls addUserToMapping
6. writes the logEntry (if wanted :/)
7. redirects browser to 'oopsregthanks'