Force mode IOs (UniversalRobots#75)

* Added gpio flags for force_mode

* Added io field for disabling force mode

* Added IO fields for force_mode damping and gain_scaling

urdf/ur.ros2_control.xacro

@@ -336,6 +336,38 @@
           <command_interface name="zero_ftsensor_async_success"/>
         </gpio>
 
+        <gpio name="${tf_prefix}force_mode">
+          <command_interface name="task_frame_x"/>
+          <command_interface name="task_frame_y"/>
+          <command_interface name="task_frame_z"/>
+          <command_interface name="task_frame_rx"/>
+          <command_interface name="task_frame_ry"/>
+          <command_interface name="task_frame_rz"/>
+          <command_interface name="selection_vector_x"/>
+          <command_interface name="selection_vector_y"/>
+          <command_interface name="selection_vector_z"/>
+          <command_interface name="selection_vector_rx"/>
+          <command_interface name="selection_vector_ry"/>
+          <command_interface name="selection_vector_rz"/>
+          <command_interface name="wrench_x"/>
+          <command_interface name="wrench_y"/>
+          <command_interface name="wrench_z"/>
+          <command_interface name="wrench_rx"/>
+          <command_interface name="wrench_ry"/>
+          <command_interface name="wrench_rz"/>
+          <command_interface name="limits_x"/>
+          <command_interface name="limits_y"/>
+          <command_interface name="limits_z"/>
+          <command_interface name="limits_rx"/>
+          <command_interface name="limits_ry"/>
+          <command_interface name="limits_rz"/>
+          <command_interface name="type"/>
+          <command_interface name="disable_cmd"/>
+          <command_interface name="force_mode_async_success"/>
+          <command_interface name="damping"/>
+          <command_interface name="gain_scaling"/>
+        </gpio>
+
         <gpio name="${tf_prefix}system_interface">
           <state_interface name="initialized"/>
         </gpio>