Unfortunately, the EcsRunLauncher doesn't support the local development
instructions becuase the local Docker containers can't use
to introspect information about itself. Additionally, we can't use the
AWS SDK to launch local docker containers via the ECS API.
This shouldn't be merged until https://dagster.phacility.com/D8404 lands
and is published to pypi - prior to that, containers will fail to stand up
because the EcsRunLauncher class won't exist yet.