Remove passwords from build image

[jreadey]

Including usernames and passwords as part of the Docker image is problematic - for one it makes it impossible to distribute images via Docker hub or other public repo.

Rather than building in the password file, either mount the file (for Docker deployments) or create a secret (for Kubernetes).

[jreadey]

Docker compose files have been updated to mount password file. E.g: https://github.com/HDFGroup/hsds/blob/master/docker-compose.yml.
And Kubernetes_deployment scripts use password secret.