Bug 25906: Style corrections for OPAC serial pages

Bug 25906: Style corrections for OPAC serial pages

This patch makes some CSS changes to the OPAC SCSS and to the OPAC
"full serial issues" page to improve the style.

I've expanded the in-page CSS on the full serial issues page for
readability and added Template Toolkit's "collapse" filter to remove the
whitespace on rendering.

To test, apply the patch and rebuild the OPAC CSS
(https://wiki.koha-community.org/wiki/Working_with_SCSS_in_the_OPAC_and_staff_client)

- Locate a serial record in the OPAC.
- Click "More details" to view the issues page.
- Confirm that the "view" tabs look correct, with consistent padding.
- Click the "Full history" tab.
- In the sidebar, the filter should have full-width dropdowns and clear
  button.

Signed-off-by: Timothy Alexis Vass <timothy_alexis.vass@ub.lu.se>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>