Bug 32042: Add page-section to catalog's item detail view

Bug 32042: Add page-section to catalog's item detail view

This patch adds a couple of .page-section divs to the item detail view
in the catalog. A "clearfix" class is also added in order to make sure
the sections don't overlap.

To test, apply the patch and locate a bibliographic record in the
catalog.

- In the sidebar menu of the bibliographic detail view, click "Items."
- On the item detail page, confirm that the information is displayed
  well.

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>