Use custom message consumer for outputers.

Instead of shared task, use a consumer to output events. This allows for
properly cleaning up of resources when yalp-outputer is stopped.
fix tests
lint
remove print
call shutdown in output tests
coverage config
tests for config parsing
Remove cli related code from scripts.

Cli may be going away, really just useful for quick testing
Merge pull request #8 from yalp-log/outputers-cleanup

Outputers cleanup