simplify DI, add sensu check to poll netconf

brian_polling_manager/configuration.py

brian_polling_manager/interface_stats/cli.py

brian_polling_manager/interface_stats/config-example.json

brian_polling_manager/interface_stats/config.py

brian_polling_manager/interface_stats/services.py

brian_polling_manager/interface_stats/services/validation.py

brian_polling_manager/interface_stats/services/writers.py

brian_polling_manager/interfaces.py

requirements.txt

setup.py

test/conftest.py

test/interface_stats/conftest.py

test/interface_stats/test_interface_stats.py

test/interface_stats/test_interface_stats_e2e.py

test/interface_stats/test_services.py

test/test_sensu_checks.py