Do not use a stamped wrench

Since the geometric representation if the wrench is dependong on both,
the type and the task frame, it doesn't relly make sense to use a
stamped wrench here.

srv/SetForceMode.srv

@@ -11,7 +11,7 @@ bool selection_vector_rz 0
 
 # The forces/torques the robot will apply to its environment. For geometric interpretation, please
 # see parameter `type`
-geometry_msgs/WrenchStamped wrench
+geometry_msgs/Wrench wrench
 
 # An integer [1;3] specifying how the robot interprets the force frame
 # 1: The force frame is transformed in a way such that its y-axis is aligned with a vector pointing