Bug 12494 - Remove yuipath system preference

Bug 12494 - Remove yuipath system preference

With the OPAC prog template going away, the only remaining use of the
yuipath preference is on the basketgroups template. The yuipath
preference should be removed and the local path hard-coded.

This patch:
  - removes yuipath handling from C4/Templates.pm
  - removes the preference from sysprefs.sql
  - deletes the preference via updatedatabase.pl
  - removes the preference from the staff client preferences file
  - removes unused references to the YUI assets from the help file
    header include
  - adds the local YUI asset path to acqui/basketgroup.tt

To test, apply the patch and run the database update. View some online
help pages and confirm that they function correctly. View the
basketgroups page (Acquisition -> Vendor -> Basket groups), edit a
basket group, and confirm that basket drag and drop operations work
correctly.

Signed-off-by: Aleisha <aleishaamohia@hotmail.com>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Passes all tests and QA script.
Online help and basket group drag&drop functionality still work correctly.

Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>