[FEA] add type adaptation feature in Humble.

[ZhenshengLee]

https://github.com/ros-infrastructure/rep/blob/master/rep-2007.rst

[ZhenshengLee]

see
ros2/demos#482
ros2/demos#583

ros-perception/vision_opencv#441

I don't see the priority, cause it doesn't improve the performance.

[ZhenshengLee]

But in rclcpp-intra-process, type conversion is avoided, see following

ros2/rclcpp#1849
ros2/ros2_documentation#2377
ros2/rclcpp#1664

this make it possible to improve cuda performance, because cudamemcpy canbe avoided too!

see this example of intra-process-cuda-image-pipeline https://github.com/NVIDIA-ISAAC-ROS/ros2_examples/tree/humble/rclcpp/type_adaptation/accelerated_pipeline

Anyway , rclcpp-intra-process is not for ros2_shm_msgs.

[ZhenshengLee]

zero-copy can be achieved with intra-process since dashing(stable in foxy), the type-adaption feature is mostly for saving costs in the GPU processing of image/pointclouds. this issue will be merged into #18

closing this.