MotorPlugin: use MotorPlugin in iris_with_gimbal

- Configure one motor to use the new MotorPlugin.

Signed-off-by: Rhys Mainwaring <rhys.mainwaring@me.com>

Author: srmainwaring

models/iris_with_gimbal/model.sdf

@@ -311,6 +311,25 @@
       </plugin> -->
 <!-- //////////////////////////////////////////////// -->
 
+    <plugin name="MotorPlugin" filename="MotorPlugin">
+      <joint_name>iris_with_standoffs::rotor_0_joint</joint_name>
+      <use_actuator_msg>0</use_actuator_msg>
+      <disable_braking>0</disable_braking>
+      <topic>/rotor_0_joint/cmd_vel</topic>
+      <p_gain>0.20</p_gain>
+      <i_gain>0</i_gain>
+      <d_gain>0</d_gain>
+      <i_max>0</i_max>
+      <i_min>0</i_min>
+      <cmd_max>2.5</cmd_max>
+      <cmd_min>-2.5</cmd_min>
+      <!-- T-Motor 2216 920KV as used on a Hexsoon 450 -->
+      <voltage_max>16.8</voltage_max>
+      <speed_constant>920</speed_constant>
+      <coil_resistance>1.5e-3</coil_resistance>
+      <no_load_current>0.8</no_load_current>
+    </plugin>
+
     <!-- <plugin
       filename="gz-sim-joint-controller-system"
       name="gz::sim::systems::JointController">
@@ -327,7 +346,7 @@
       <i_min>0</i_min>
       <cmd_max>2.5</cmd_max>
       <cmd_min>-2.5</cmd_min>
-    </plugin>
+    </plugin> -->
     <plugin
       filename="gz-sim-joint-controller-system"
       name="gz::sim::systems::JointController">
@@ -378,7 +397,7 @@
       <i_min>0</i_min>
       <cmd_max>2.5</cmd_max>
       <cmd_min>-2.5</cmd_min>
-    </plugin> -->
+    </plugin>
 
     <plugin
       filename="gz-sim-joint-position-controller-system"