Bug 28036: Improve breadcrumbs of serial claims page

Bug 28036: Improve breadcrumbs of serial claims page

This patch modifies the serial claims script and templates so that
better context can be shown in the page title and page breadcrumbs when
a vendor has been selected.

To test, apply the patch and go to Serials -> Claims.

- The initial state of the page title and breadcrumbs should show
  "Serials > Claims."
- Select a vendor. The page title and breadcrumbs show show "Serials >
  Claims > Claims for <vendor name>."

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>