Webmail should fail if special folders aren't found

[mikegioia]

The webmail app will not really work without name matching the special folders. Unless there was some other way built in to assign a special type to a folder, then we currently rely on matching based off the name.

• Assess difficulty in assigning a special type (i.e. Drafts, Sent, All Mail, Trash, Spam) to folders via a pre-loading screen/form
• If doable, add a pre-controller hook that renders a settings form if any of the special folders are not found
• The form should:
  • show folders that are ok
  • add a select box containing all un-taken folders adjacent to each needed special folder
  • if the same folder is use twice, produce an error message and go back to the form
  • once all special folders are handled, hook should allow regular access to the app