Add a "Curve Radius" measurement tool

[ritchiewilson]

Feature description

It would be helpful if one of measurement tool options let you measure a curve radius. This is would be used to find curvatures on satellite images, especially for measuring roads or railways. Some examples of the importance of this measurement can be found here:
https://en.wikipedia.org/wiki/Minimum_railway_curve_radius

How it could work would be to make it one of the measurement tools in the dropdown, "Measure Curve Radius". A measurement window would pop up. The user could click three points on the map along the curve they wish to measure (e.g. a road or rail). The tool would create the circle described by those three points, and the radius measurement would appear in the popped-up window.

Thanks! (And sorry if I've just missed this feature elsewhere)

Additional context

No response