Toolkit: update overrides for scroll fixes

Toolkit: update overrides for scroll fixes

while some scrolling issues where fixed since 6.0.1, some where introduced,
namely:
* for firefox, the correct event to listen to is 'wheel' not 'mousewheel'
* the spinner scroll direction was incorrect
* the boxOverflow scroll direction was incorrect
* the boxOverflow scroll amount was too high

functions were copied from extjs source, eslintified, and adapted

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>