Bug 27740: Corrected tags & hierarchy of headings

Bug 27740: Corrected tags & hierarchy of headings

Bug 27610 corrected the <h1> tags in each of the OPAC files. This patch
corrects the hierarchy of the rest of the headings on each of the pages.

To test:
1) Go to the OPAC
2) Apply Bug 27610 patch
3) Apply patch (Bug 27740)
4) Go to each of the pages and check that the headings under <h1> are in
   the correct order and hierarchy

Sponsored-by: Catalyst IT
Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>