Make the README more informative

[minggangw]

From the recent feedback, we are going to add some sections to the README to clarify some circumstances:

• How to install the rclnodejs module from npm or Github in order to align with a specific ROS 2 release, e.g. bouncy-bolson
• Run the rclnodejs module on ROS 2 which was built from source
• Update of ActionLib and mark as deprecated as the rcl has offered the functions directly.