Investigate porting Action functionality to ROS2

[mkhansenbot]

We're depending on Actions being implemented in ROS2, which aren't implemented yet. We need to try and pull that in, and some work is needed to design how they should be implemented. I'm linking this issue to the issue in ROS2 for this discussion.

[mkhansenbot]

Update: Here is a branch where I've added a node->create_action_server() and node->create_action_client(). https://github.com/mkhansen-intel/rclcpp/tree/actions

And here is a branch for examples for both. https://github.com/mkhansen-intel/examples/tree/action_examples

See here for the full update: ros2/design#183 (comment)

[mkhansenbot]

This is still in discussion with OSRF so I'm pushing it to October milestone.

[mkhansenbot]

Closing this, OSRF is tracking