Bug 37841: Switch OPAC language menu alignment in header and footer

Bug 37841: Switch OPAC language menu alignment in header and footer

The OPAC language menu is now generated by the same include file in both
the header and the footer. We have a switch for the menu's direction
based on this context, but we also need a switch for alignment: The menu
should extend left into the page from the header, and right into the
page from the footer.

To test you should have at least one additional language installed and
enabled. To reproduce the bug I recomment en-GB because the language
description is long enough to trigger the misalignment.

- Apply the patch and set the 'opaclanguagesdisplay' system preference
  to "Allow" and the 'OpacLangSelectorMode' preference to "both top and
  footer".
- Go to the OPAC and test the language selector menus in the header and
  footer.
  - The expanded menu in the header should extend to the left of the
    "Languages" menu trigger.
  - The expanded menu in the footer should extend to the right of the
    "Languages" menu trigger.

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