[FEATURE] Krita can now read icc-color and write stopgradients with icc-color.

[Wolthera]

Hey,

I just merged https://invent.kde.org/graphics/krita/-/merge_requests/675

This added icc-color parsing, (as per SVG 1.1). Krita will now use the
icc-colors inside SVG files it opens and inside the SVG stop
gradients. It can also save non-sRGB colors to stopgradients now. It
does not save non-sRGB colors to regular SVG files, because our vector
shapes are not color managed (which would be... quite a project), so
that makes no sense. But this should help with the HDR gradient
project.

This had changes in pigment, so it WILL lead to a huge rebuild.

At some point, I'll work on css-color-4, which is what Inkscape devs
are also aiming to support, but that is a much more complicated spec,
and also not finished yet, so not sure yet when to start working on
it.
-- 
Wolthera