Add support for ROS 2 (Humble)

[HansRobo]

abstruct

I imported derverbles from choreonoid/choreonoid_ros2 and added some fixes. With this pull-request, this repository is configured to be buildable on both ROS 1 and ROS 2.

The major differences between ROS 1 version and ROS 2 version are as follows.

ROS configuration

ROS 1

• A choreonoid app containing a ROS plugin behaves as a single ROS context, a node.
• The plugin initialization blocks the choreonoid app launch if there is no connection to roscore.

ROS 2

• Since there is no ROS 2-related processing in plugin initialization, it does not block the app launch.
• ROS 2 plugin can be loaded and used in choreonoid app without modification for the plugin.
• Each of WorldROS2Item and BodyROS2Item operates as its own ROS 2 context and node for each instance of the item.

ros_control support

ROS 1

ros_control support is available now.

ROS 2

ros_control support is not available now. However, we plan to support it in the future.

Build instruction for ROS 2 (Humble, Ubuntu22.04)

mkdir -p cnoid_ws/src
cd cnoid_ws/src
git clone git@github.com:choreonoid/choreonoid.git
git clone -b merge_choreonoid_ros2 git@github.com:choreonoid/choreonoid_ros.git
cd ..
source /opt/ros/humble/setup.bash
rosdep install -iy --from-paths src
colcon build --symlink-install

Note: Please ignore the error from choreonoid with catkin, when running rosdep (Fixed in https://github.com/choreonoid/choreonoid/pull/36)