This continues work done on the native-ros branch by Samer and myself, and brings it to a functioning state.
The first 7 commits are from there, just rebased on top of development.

Each device is exposed on the /ros_discovery_info topic as a separate node.
The nodes are named in a similar fashion as DDS topic-roots, /realsense/<model>_<s/n>.
You can use rqt_reconfigure to see the nodes. The tool will list, describe, and get all parameters, and you can use it to also set them.
The parameters themselves use names of <stream>/<option-name>.
Changes to option values are updated via the /parameter_events ROS2 topic. Notifications seem to be working.

Additionally, each stream has a <stream>/profile parameter that lets the use see the current active profile (as JSON) and change it.
This is the only are where additional thought and investigation might be required inside the stream-sensor-bridge. But it's working well for the most part. I can describe some of the difficulties I had, but for now I decided it's good enough for PR as it's functional.

Testing was all manual.

ROS2 topics were added minus any type-objects.