Add an option to give a list of topics when using `rosbags-convert`

Adresses issue #38 (closed)

I added a way to specify an optional list of topic to convert. The goal is to provide a way to convert only some topics from a rosbag, as way to replace what could be done with the rosbag filter command in ROS1 A good use case for this kind of feature are robotics laboratories that may have huge rosbags with all recordable topics from a robot.

Further improvements would be to test topics against glob patterns, so that glob patterns could be provided to include multiple topics at once.

Signed-off-by: Damien LaRocque phicoltan@gmail.com