Make sure we pass on disabling of password encoding to spawned containers

Conflicts:
	fabric/fabric-docker-provider/src/main/java/io/fabric8/docker/provider/DockerConstants.java
Missed update to docker provider
Use prefix to ensure we don't encode pw twice
Add prefix to encoded pw
Add pw encoder test
Fix obfuscating of zookeeper password.

Conflicts:
	fabric/fabric-boot-commands/src/main/java/io/fabric8/boot/commands/CreateAction.java