Enhance IIWA Robot Configuration and Launch Files

- Updated iiwa7 URDF Xacro to include command and state interfaces for position and effort with defined limits for all joints.
- Modified setting_loader.py to include new fields for command_mode and description in the RobotCfg dataclass and settings loading process.
- Created iiwa.launch.py to manage the launch of the IIWA robot, integrating MoveIt configurations and RViz support.
- Added iiwa_controllers.launch.py to set up the controller manager and spawner for the IIWA robot.
- Introduced iiwa_hardware_interface_plugin.xml to define the hardware interface for the KUKA IIWA 7 robot.
- Added iiwa7_fri.urdf.xacro to support FRI (Fast Robot Interface) with appropriate command and state interfaces for each joint.

src/iiwa_bringup/launch/supported/iiwa_controllers.launch.py

@@ -0,0 +1,66 @@
+from launch.substitutions import LaunchConfiguration
+from launch.actions import RegisterEventHandler
+from launch.event_handlers import OnProcessExit
+from launch.actions import OpaqueFunction
+from launch import LaunchDescription
+from launch_ros.actions import Node
+
+
+from iiwa_utils import converter
+
+
+def _setup_controllers(context, *args, **kwargs):
+    robot_name = LaunchConfiguration("robot_name").perform(context)
+    description = LaunchConfiguration("description").perform(context)
+    initial_positions_file = LaunchConfiguration("initial_positions_file").perform(
+        context
+    )
+    controller_path = LaunchConfiguration("controller_path").perform(context)
+
+    robot_description = converter.load_robot_description(
+        model_path=description,
+        robot_name=robot_name,
+        xacro_args={"initial_positions_file": initial_positions_file},
+    )
+
+    ros2_control_node = Node(
+        package="controller_manager",
+        executable="ros2_control_node",
+        output="screen",
+        parameters=[
+            {"robot_description": robot_description},
+            controller_path,
+        ],
+    )
+
+    
+    joint_state_broadcaster_spawner = Node(
+        package="controller_manager",
+        executable="spawner",
+        arguments=["joint_state_broadcaster", "--controller-manager", "/controller_manager"],
+        output="screen",
+    )
+
+    arm_controller_spawner = Node(
+        package="controller_manager",
+        executable="spawner",
+        arguments=["iiwa_arm_controller", "--controller-manager", "/controller_manager"],
+        output="screen",
+    )
+
+    arm_controller_after_jsb = RegisterEventHandler(
+        OnProcessExit(
+            target_action=joint_state_broadcaster_spawner,
+            on_exit=[arm_controller_spawner],
+        )
+    )
+
+    return [
+        ros2_control_node,
+        joint_state_broadcaster_spawner,
+        arm_controller_after_jsb,
+    ]
+
+
+def generate_launch_description():
+    return LaunchDescription([OpaqueFunction(function=_setup_controllers)])