Move several vtkRenderingContext2D dependencies

Made most of the vtkRenderingContext2D dependencies private. Some
minor moves for vtkChartsCore too.

Change-Id: I41f3066e67d8537830c076829fafac034fadf41d
Move the Qt module to private dependency

Change-Id: I5487becf01f9f7d83f3fe020cd5031b2e3986e0a
Merge topic 'context2d-private-deps' into master

9eda1c02 Move the Qt module to private dependency
38505fc6 Move several vtkRenderingContext2D dependencies