Feature: Arc radius from 3 points

[GraceDM]

https://forum.seamly.io/t/how-to-draw-an-arc-through-three-points/9761

A tool that will establish a point at the centre of 3 other points to be used to draw an arc to cover the 3 points. This request was solved by using an example from this website: https://opentextbc.ca/patterndevelopment/chapter/draw-an-arc-through-3-points/