Add ros2_control interfaces for tool_contact (#275)

Author: urfeex

urdf/ur.ros2_control.xacro

@@ -294,6 +294,12 @@
           <command_interface name="abort"/>
         </gpio>
 
+        <gpio name="${tf_prefix}tool_contact">
+          <command_interface name="tool_contact_set_state"/>
+          <state_interface name="tool_contact_result"/>
+          <state_interface name="tool_contact_state"/>
+        </gpio>
+
         <gpio name="${tf_prefix}system_interface">
           <state_interface name="initialized"/>
         </gpio>