Improve framerate of stabilizer

This change aims to improve the framerate of the stabilizer visual
feedback.

 - Perform delayed paint during `KisToolFreehandHelper::paint` (pointer
   event) and use a timer for backup.
 - Removed the `stabilizerDelayedPaintInterval` config option.
 - Added the `stabilizerDelayedPaint` config option for disabling the
   delayed painting,

CCBUG: 369349
Maniphest Tasks: T6440
Differential Revision: https://phabricator.kde.org/D6534