Gamut masking: mask rotation, advanced selector, tweaks

Summary:
This diff includes:

• implementation for the advanced color selector (T9643),
• common gamut masking toolbar for both advanced and artistic selectors (M135, M136),
• mask rotation (as defined in T9642).

There are also some minor tweaks:

• adaptive highlight of selected swatches - dark when the selected color is light, light when the selected color is dark;
• gamut mask preview while editing is always on;
• the blip in the artistic color selector is always on;
• the text size of the comparative gray scale in the artistic selector is computed so it fits inside the rectangles.

Reviewers: Krita, rempt

Reviewed By: Krita, rempt

Subscribers: rempt, kamathraghavendra, lsegovia, scottpetrovic

Tags: Krita

Differential Revision: https://phabricator.kde.org/D15860