Cannot specify log level via the CLI

[piraka9011]

There is currently no mechanism to specify the log level ros2bag via the CLI.

I have attempted to configure the level using __log_level:=debug and --log-level flags, however they both are assumed to be topics by Python's argparser.

This may require specifying the log level in ros2bag and propogating it accordingly to rosbag2_transport where we could then use rcutils_logging_set_logger_level() with the transport_node.

[emersonknapp]

Now that the Recorder and Player are Nodes, we should be pretty close to being able to configure the log level via parameters to those nodes. Though, the workflow is not quite connected yet.