Custom docker image for mzbench nodes. It is very useful to have ability to start nodes with a newer image (e.g. when developing a new worker). Now it is possible if you specify "worker_image" in the bench environment variables.
When you're working in the k8s, you have a predefined docker image, and it may contain a lot of different workers in one folder. Now we have a new option "load_workers_subdirs" that will enable loading all the workers that reside in the <default_workers_dir>/*/ebin
<default_workers_dir>/*/ebin