Update the registration module to permit editing all the sections

Currently, the patient registration module allows editing one section at a time. We worked on an implementation where we needed a patient update form where all the sections can be edited. We therefore needed a controller that handles the edit of the entire patient form. We updated RegisterPatientFragmentController, and added a new method that handles the edit of the entire patient registration form (without modifying the existing code that handles adding a new registration). We added an extra query parameter: patientIdNumber which when included, causes the controller to edit the existing patient. This solution is backward compatible: it doesn't alter the current patient registration flow and adds the possibility to also edit a patient. We thought this approach could benefit the community. Please find attached a PR for review (see: https://github.com/openmrs/openmrs-module-registrationapp/pull/36).