Evaluate GRLAA for polyline AA

@bagnell what do you think of this: https://www.imgtec.com/blog/grlaa-for-anti-aliasing-in-nav-applications/

I also did something like this in the virtual globe book.

The issue names no source files, tests, or entry points; begin with the linked GRLAA article and the referenced virtual globe book material. Define whether Cesium should adopt GRLAA for polyline anti-aliasing and record concrete implementation scope and acceptance criteria before coding.

Written by the indexing model from the issue text.