Parameterise domain suffix and passwords

[andywis]

It should be possible to change the domain suffix (see Jenkinsfile).

It should also be possible to supply passwords for the "admin" and "demo" users. If supplied, deploy-openshift.sh should not generate random passwords.

Store as secrets, like the other data passed from "setup-ci" to the Jenkinsfile.

A side-effect of supplying passwords is that the "collect passwords" stage is no longer needed, and the 'validate openshift deployment' stage doesn't need the NEW_PASSWORD.