Work around low framerate of stabilizer

Work around low framerate of stabilizer by delaying and painting the
stroke progressively.

The KisStabilizerDelayedPaintHelper class collects the sampled events
and distributes them evenly with a timestamp attached, then a timer firing
at a closer interval would paint the line bit by bit in order to give a
smoother user feedback.

The config option stabilizerDelayedPaintInterval with default value 20
controls the paint interval. The delayed painting is disabled if this
value is higher than stabilizerSampleSize, which means it is disabled by
default on non-Windows system.

BUG: 369349
Maniphest Tasks: T4182
Differential Revision: https://phabricator.kde.org/D3321