DDBNEXT-136: fallback for i18n, if the message key can not be found.

  When the app can not find the key in message properties, then it
  should use the field's name instead.
DDBNEXT-136: remove unneeded exceptions
DDBNEXT-136: capitalize the letter of the field's name
DDBNEXT-136: add missing translation
Merge branch 'bugfix/ddbnext-136' into develop

Conflicts:
	grails-app/controllers/de/ddb/next/ItemController.groovy
	grails-app/views/item/item.gsp