[QML] ColorAnimation with HSL

A feature request for animating between two colors e.g. red -> green using a HSL interpolation rather than RGB interpolation so that we animate the Hue only so as to avoid the ugly brown color you otherwise get with the ColorAnimation.

Current with RGB

ColorAnimation {
from: "red"
to: "green"
}  // gives ugly brown mid-range

Suggestions :

 HSLColorAnimation {
 from: "red"
 to: "green"
 } // does not give ugly brown mid-range

or 

ColorAnimation {
from: "red"
to: "green"
hsl: true // defaults to false for backward compatibility
}

It should also consider animating the S and L parts too.

Using QML Colorize or making own in C++ were considered but here we are looking for more elegant approach to animate a color property based on other color scheme