Bug 26572: Add autocomplete to librarian field in log viewer

Bug 26572: Add autocomplete to librarian field in log viewer

This patch adds patron autocomplete to the librarian field in the log
viewer search form.

Also changed: Some HTML markup errors in the template have been
corrected: Labels with invalid corresponding ids or with no valid id.

To test, apply the patch and go to Tools -> Log Viewer.

Type a name or cardnumber into the "Librarian" form field. This should
trigger an autocomplete dropdown.

Select a patron and confirm that the field is populated with the correct
borrowernumber.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>