Dynamic playback of locally-unknown types

[emersonknapp]

Description

If a bag has TypeDescription stored inside as schemas, we would like to be able to create publishers and play that bag back, even if it is not playing in an install space that has all types from the bag.

Related Issues

Related to #1373

Completion Criteria

Rosbag2 can play back any bag, even if the message types are not installed locally.

Implementation Notes / Suggestions

Will need to extend the idea of ros2/ros2#1374 to a "Dynamic Publisher" and then use that work.

Testing Notes / Suggestions