Bug 17487: Styling moved from style attribute into staff-global.css

Bug 17487: Styling moved from style attribute into staff-global.css

Test plan:
1) Apply patch
2) Display Z39.50 search dialogs:
   - cataloguing / new from Z39.50
   - authorities / new from Z39.50
   - acquisition / new from an external source
3) Select all / Clear all should be placed below "Search targets" header
4) [Optionally] Set some style in IntranetUserCSS for class z3950checks

https://bugs.koha-community.org/show_bug.cgi?id=17487

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>