Adding a new rigid body to the world

In cram/cram_3d_world/cram_bullet_reasoning/src/objects.lisp

```lisp (defmethod add-object <sup>1)</sup> name pose

                     &key (mass 0.00001) (radius 0.01) color)
;; (let ((compound-shape (make-instance 'compound-shape)))
;;   (dotimes (i 8)
;;     (add-child-shape
;;      compound-shape
;;       (cl-transforms:make-pose
;;         (cl-transforms:make-3d-vector 0 0 0)
;;         (cl-transforms:make-quaternion 0 0 0 1))
;;        (make-instance 'colored-sphere-shape
;;                                    :radius radius :color '(1 0 0 0.5))))
        
  ;; ;; Adds the basket to the specified world
  ;;   (make-item world name (list type)
  ;;              (list
  ;;               (make-instance 'rigid-body
  ;;                 :name name :mass mass :pose (ensure-pose pose)
  ;;                 :collision-shape compound-shape)))))
      
(make-item world name (list type)
            (list
              (make-instance
                  'rigid-body
                :name 'waterdrop1 :mass 0.00000000001 :pose (ensure-pose pose)
                :collision-shape (make-instance 'colored-sphere-shape
                                   :radius radius :color color))
              )))
              ```