Including st_minimum_bounding_radius

[lcgodoy]

Hello everyone,

This PR implements st_minimum_bounding_radius, a function that returns the center and radius of the minimum bounding circle for a geometry.

Currently, users requiring only the circle parameters must generate the full polygon via st_minimum_bounding_circle (with the st_buffer overhead) and then post-process it to derive the circles' centroid and area. This implementation allows for direct, efficient retrieval of these parameters and matches the PostGIS ST_MinimumBoundingRadius function.

I updated the documentation accordingly by documenting st_minimum_bounding_radius alongside st_minimum_bounding_circle. Note that for sfg and sfc inputs, the function currently returns only the circles’ centers to maintain class consistency and a warning is issued in these cases to explain the behavior.

I have not included any tests with the function because I was unsure about helpful tests in this case.

Please let me know if you have any suggestions or if fixes are needed to get this merged.

Cheers.