refactoring casa-envoy

.../cli/executables/pexable/casa_envoy/casa_envoy/auditor.py

...i/executables/pexable/casa_envoy/casa_envoy/interfaces.py

...li/executables/pexable/casa_envoy/casa_envoy/launchers.py

.../cli/executables/pexable/casa_envoy/casa_envoy/palaver.py

...i/executables/pexable/casa_envoy/test/image-metadata.json

apps/cli/executables/pexable/casa_envoy/test/test.json

apps/cli/executables/pexable/casa_envoy/test/test_auditor.py

...li/executables/pexable/casa_envoy/test/test_casa_envoy.py

...cli/executables/pexable/casa_envoy/test/test_launchers.py