Allow configuration of the severity level for eProsima logging

[deng02]

Feature Request

Currently the eProsima logging level is hardcoded to ERROR:
https://github.com/ros2/rmw_fastrtps/blob/master/rmw_fastrtps_cpp/src/rmw_node.cpp#L66

For troubleshooting, it would be useful to be able to change the severity level of the eProsima to INFO or DEBUG, either independently of ROS2 or in conjunction with.

[dirk-thomas]

I think the best path forward is to implement a custom LogConsumer for FastRTPS which uses the ROS logging API provided by rcutils. Currently rcutils doesn't offer name-specific severity levels but that feature is planned to be added in the future.

If you would like to see this feature rather earlier than later we would appreciate a PR for it.

[MiguelCompany]

I think this can be done calling rmw_set_log_severity which in turn calls this

[dirk-thomas]

Implemented a while ago in #156.