Add a radial "grid" type to the grid tool

[Notgnoshi]

Concentric circles, with radial spokes. Graph output is likely the most useful.

With a higher density than typical grids, it may make for some interesting asemic glyphs.

At a low density, it should make concentric squares, which would still probably make interesting glyphs?

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I can think of two approaches, both of which I think I want to do

• [ ] Re-interpret a set of (x, y) geometries as if they are (r, theta)
  • [ ] Would need a densify / simplify tool (geo provides Simplify and SimplifyVw algorithms)
  • [ ] Use transform to convert (x, y) <-> (r, theta)
  • [ ] Use transform to apply arbitrary rhai functions to each coordinate (Could use some of the transformations from Morphing: A Guide to Mathematical Transformations for Architects and Designers)
• [ ] Generate a radial grid in (x, y) coordinates. Tunable parameters:
  • [ ] number of spokes
  • [ ] number of points on a spoke
  • [ ] number of concentric rings
  • [ ] number of points between axes OR the distance between points