Save global color to KRA file
Summary:
This is a patch on top of my custom colors patch.
The shared/global assistant color for painting assistants is stored outside of the assistant data model. Because of this I had to add a new property to save to in the KRA saver and loader.
I also had to fix up a few initialization areas in the UI so the loaded values didn't get wiped out.
I also removed a couple "legacy" comments in the KRA saver that got me confused. boud confirmed that those notes were in the calligra days
Test Plan:
Have multiple assistants. A couple with a shared color and one with a custom color.
Saved and loaded the file and made sure it kept the same value.
Reviewers: Krita, dkazakov
Subscribers: dkazakov
Tags: Krita
Differential Revision: https://phabricator.kde.org/D13437