Bug 26093: Markup error after Bug 24279 creates formatting problem

Bug 26093: Markup error after Bug 24279 creates formatting problem

This patch makes a few minor changes to the markup of the item detail
page in order for everything to be valid and styled correctly:

- Remove unnecessary and invalid <br clear="both"/>
- Move heading inside container so that floats clear correctly
- Change <span> tag back to <div> to enable the correct style.

To test, apply the patch and view the item details page for a title with
multiple items.

 - Each section starting with "Barcode" should be bordered above by a
   two-pixel gray line
 - The "statuses" section should be styled like the areas above and
   below, not as an ordered list.

Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>