Improve cleanup for docker-compose. (testcontainers#394)
* Improve cleanup for docker-compose.
Reduce unnecessary cleanup attempts which cause errors to be logged.
docker-compose down is now trusted to have cleanup up properly if it
exits with a 0 status code.
* Swap order of removal of containers vs networks if docker-compose down failed
* Update changelog
* Further improvements following code review
* Reinstate semi-public methods and mark as deprecated
Improve comments to aid clarity in removeNetwork method