Default EllipseGeometry granularity

For #2173.

The `EllipseGeometry` and `EllipseOutlineGeometry` were creating way to many points that were much closer than the given granularity. Computing the arc-length of the ellipse is too expensive to be practical. Estimating it using the arc length of the sphere is too inaccurate and creates sharp edges when either the semi-major or semi-minor axis is much bigger than the other. Instead, I chose to scale the angle delta to make the distance along the ellipse boundary more closely match the granularity.
We should probably comment as to why we are doing this.