Bug 20154: Stay in the open tab when editing authority record

Bug 20154: Stay in the open tab when editing authority record

This patch adds some JavaScript to the authority record detail page in
the staff interface so that clicking "Edit" will take you to the
authority edit page while keeping the same tab open.

To test, apply the patch and locate an authority record in your catalog.

 - Click any of the numbered tabs besides tab 0.
 - Choose "Edit record" from the "Edit" dropdown menu.
 - When the authorities edit page loads the same tab should be
   preselected.

Signed-off-by: Marjorie <marjorie.barry-vila@collecto.ca>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>