Listen to changes in page settings in DiagramSceneGraphProvider

Listen to changes in page settings in DiagramSceneGraphProvider

This is needed for use cases where diagrams are transformed to SVG and
viewed through browsers.

These changes also fix PDF printing to force page border rendering off
when not fitting PDF pages to diagram content, but to diagram page size.
This avoids printing ugly black half-visible borders around diagrams
where page borders are enabled.

gitlab #563

Change-Id: I7f666dec34c650489264f3d23cbd72d5102b2f14
(cherry picked from commit 2ccc058ac6c303b64a70ad0f0c48ca501bf4aa6a)