* misc backend fixes:
- fix running w/o local minio
- ensure crawler image pull policy is configurable, loaded via chart value
- use digitalocean repo for main backend image (for now)
- add bucket_name to config only if using default bucket
* enable all behaviors, support 'access_endpoint_url' for default storages
* debugging: add 'no_delete_jobs' setting for k8s and docker to disable deletion of completed jobs