LP2042879 Shelving Location Groups Admin accessibility

LP2042879 Shelving Location Groups Admin accessibility

Fixes duplicate groups in the All Shelving Locations list.

Corrects various accessibility issues in Admin > Local > Shelving
Location Groups:

* Keyboard support for all buttons, including up/down arrow key support
  for drag and drop
* Labels for all inputs, including checkboxes
* List and table markup, to provide context and navigation options for
  screen reader users
* Headings, for screen reader navigation
* Responsive layout to allow content to reflow when text is zoomed in

This also revises the drag and drop logic so that the position numbers
increment from the last unchanged position rather than their previous
value (which could result in unnecessarily large numbers).

Release-note: Refactors Shelving Location Groups Admin for accessibility

Signed-off-by: Stephanie Leary <stephanie.leary@equinoxoli.org>
Signed-off-by: Terran McCanna <tmccanna@georgialibraries.org>
Signed-off-by: blake <blake@mobiusconsortium.org>
Signed-off-by: Steven Mayo <smayo@georgialibraries.org>
Signed-off-by: Shula Link <slink@gchrl.org>