Add Email Address and Name field to Help form

 * Add name and email fields to help_request via migration
 * Hide detail fields that user cannot change on form
 * Add name and email fields, and ensure that they are required with
   validates_presence.

Adjust loading bar in bootstrap modal to disappear when modal loaded

 * Added $('body').modalmanager('loading'); - which toggles the loading
   bar off when called after the modal window has loaded

This is a one-liner, so adding onto dltp-225 commit which also deals
with the modal window.

dltp-225#
dltp-233#