This commit introduces AutoColor property for sketches that when
enabled ensures that sketches are updated with the color of user
preference. It ensures that sketches from different users will be
still visible on different themes.
To ensure backward compatiblity migration strategy is to compute default
value for this property based on the color. If it is non-white (the
default value in FreeCAD) we assume that the change was inentional and
that it should be kept as-is turning automatic coloring off. In other
cases it is enabled by default.
Fixes: FreeCAD#13980
bcb4ee21cc