Bug 35812: Add canonical URL for biblio details page

Bug 35812: Add canonical URL for biblio details page

This adds a nice canonical URL for search engines to use. Will prevent duplicates with different URL query parameters from getting indexed separately, will also prevent search engine confusion when opac-search.pl redirects to opac-detail.pl when there's just one result.

Should result in prettier/simpler URLs in the search engines too, plus removal of constant warnings in Google Search Console and other tools.

Signed-off-by: Pedro Amorim <pedro.amorim@ptfs-europe.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>