Bug 24155: (follow-up) Template fixes and updates

Bug 24155: (follow-up) Template fixes and updates

This patch makes a few minor changes to the OPAC and staff interface
templates:

- In both, the "Apply field weights" checkbox will only appear after the
  "More options" button has been clicked. Otherwise a hidden input sets
  the value to 1.
- In both, the checkbox now appears below the search fields.
- Checkboxes are now wrapped in the <label> tag to ensure the label is
  clickable.

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