Bug 22170: Improve display of add/edit library group modal

Bug 22170: Improve display of add/edit library group modal

Tries to bring the emodal for adding/editing library root
and sub groups more in line with the rest of Koha.

To test:
 - Go to Administration > Library groups
 - With and without patch test following actions:
   - Add a new root group
   - Edit root group
   - Add sub-group entry
   - Edit sub-group entry
- Verify that with the patch the display of the labels
  is more standard (bold and aligned to the right) and
  the input fields are a bit longer to allow for
  easier data entry.

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Mikaël Olangcay Brisebois <mikael.olangcay-brisebois@inLibro.com>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>