Bug 22209: Move stock rotation stage and item forms into modals

Bug 22209: Move stock rotation stage and item forms into modals

This patch makes a number of interface changes to the Stock Rotation
management interface:

 - "Add stage" and "Add items" forms are now triggered by clicking new
   buttons in the toolbar.
 - "Manage stages" and "Manage items" menu items have been added to a
   sidebar menu to be displayed when stages or items are being managed.
 - JavaScript has been added to move focus to the first form field in
   the modal when it is displayed. The "autofocus" attribute is not
   sufficent here because the modal is hidden by default.
 - Add messages to be shown when there are no items or stages to be
   displayed.
 - Correct "selected" attributes to use XHTML-style: selected="selected"
  (https://wiki.koha-community.org/wiki/Coding_Guidelines#HTML_Templates)

To test, apply the patch and go to Tools -> Stock rotation.

 - Create a rota if you don't already have one.
   - Manage stages for your rota.
     - If your rota has no stages you should see a message along with an
       "Add stage" button. The button should trigger the "Add stage"
       modal.
     - Test the "Add stage" button in the toolbar. It should trigger a
       modal dialog containing the form for adding a new stage. The
       cursor focus should automatically be on the "library" field.
     - Submitting the form should correctly add the stage.
     - Verify that there is a new menu in the sidebar, "Manage stages"
       and "Manage items."
   - Manage items for your rota.
     - If your rota has no items you should see a message along with an
       "Add items" button. The button should trigger the "Add items"
       modal.
     - Test the "Add items" button in the toolbar. It should trigger a
       modal dialog containing the form for adding new items. The cursor
       focus should automatically be on the "barcode" field.
     - Submitting either a barcode or a file of barcodes should work
       correctly.
     - Verify that the new menu items are shown in the sidebar.

Signed-off-by: Maryse Simard <maryse.simard@inlibro.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>