Bug 32771: Standardize structure around action fieldsets in serials

Bug 32771: Standardize structure around action fieldsets in serials

This patch updates serials templates so that fieldsets with the
"action" class are placed outside the form's main fieldset.

To test, apply the patch and rebuild the staff interface CSS. Go to
serials and check the following pages to confirm that changes to
form structure look correct:

- Navigate directly to /cgi-bin/koha/serials/serials-search.pl
  - Check the form on this page.
  - Perform a subscription search. On the search results page, check
    the sidebar form.
- Click "Manage numbering patterns" in the left-hand sidebar menu.
  - Click "New numbering pattern" and check the forms on that page.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>