Consider using an actual queue to dispatch threaded jobs

[viniarck]

This is to capture this idea/discussion when this PR #20 was being reviewed to be addressed in a future opportunity:

• Consider using an actual queue to dispatch threaded jobs, to avoid relying on sleep/wait, this should simplify and enhance the testability of the code https://github.com/kytos-ng/sdntrace/blob/master/tracing/trace_manager.py#L65-L83 since it can become event driven