Unreliable option for topics

[Myzhar]

I noticed that the Unrealiable option for the new Rviz continues to report "Prefer UDP topic transport" that I think is no more correct.

According to the DDS I think that all the Unreliable options should be splitted in two different options as combo boxes, one for Reliability and one for Durability, allowing to select Best effort or Reliable and Transient local or Volatile.

In this way you can let the user configure a subscriber that is compatible with the QOS profile of the publisher.

Ref: https://github.com/ros2/ros2/wiki/About-Quality-of-Service-Settings

[wjwwood]

Agreed, it was probably just overlooked during migration. A pull request to update this would be appreciated.

/cc @anhosi this might be something for contribution by a new contributor