Use ros2_introspection as ROS2 package

[neko-suki]

I want to use ros2_introspection as standalone ROS2 package. However, currently it's impossible because CMakelists.txt and package.xml are not provided.

Is there any plan to make ros2_introspection as a package like ros1_introspection?

[facontidavide]

https://github.com/facontidavide/ros2_introspection