Bug 26011: Remove unused jQuery plugin jquery.metadata.min.js from the OPAC

Bug 26011: Remove unused jQuery plugin jquery.metadata.min.js from the OPAC

The jQuery plugin jquery.metadata.min.js hasn't been used in
Koha in long time. This patch removes it from the OPAC.

To test, apply the patch and search for instances of "jquery.metadata."
There should be none.

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>