Fix for Bug 2970, Create a permission for modifying holds priority

Fix for Bug 2970, Create a permission for modifying holds priority

Adding two new granular permissions under 'reserveforothers,' place_holds
and modify_holds_priority. If a user does not have modify_holds_priority
permission, the option to change the priority of a hold is hidden.
Revised patch includes changes to mandatory data files including
properly translated fr-FR version.

Signed-off-by: Galen Charlton <gmcharlt@gmail.com>