ROS2 support: ROS Answers?

I agree that answers.ros.org is probably the right place for this sort of thing, for now. However, I strongly agree with @gbiggs that there should be a consistent tag (ros2?) so that the questions are easily identified.

Thinking to the future, if we ever move to another engine, then having the strong tagging will make it easier to migrate ros2 content to that engine.

– Bill