20221130 Center and sizes for STL objects not reflected accurately in Radia

[Benbenbenin0]

Object center is dependent on how how the STL is exported, sometimes isn't aligned with the shape. Can likely be fixed by using trimesh.center_mass (or .centroid) to determine appropriate center.

Object size is currently just default values, can likely use trimesh bounding box to determine actual size.

[mkeilman]

Keep in mind that the centering needs to be done on the client side since the user is dragging it aound (see radiaService.centerExtrudedPoints())

[Benbenbenin0]

Merging #4971 into this issue

[Benbenbenin0]

Shape center is now reflective of one chosen in design tab, current solution translates the radia object once created in build_stl() to the cords given by d.center