Move PathStyle from VectorData to an attribute of the Region domain

[Keavon]

VectorData has the pub style: PathStyle field which should be moved to an attribute of the Region domain. This will require updating the renderer so split the shape out into multiple SVG paths each with separate styles matching each region's style, as long as they differ within the same VectorData.

[Keavon]

Superseded by #2003, since the goals here have probably changed, although the exact design for this is still TBD and relates to how the dynamic nondestructive fills/strokes on mesh data will end up being structured at the data level.