install specific versions of portal

With several testbeds with standalone testbeds and portals deployed, there should be way to be sure that an arbitrary user can install an arbitrary version of the portal software (provided the image/version tag they are requesting is available somewhere), for several reasons.

1. testing fidelity in a virtual environment if supporting a user with a specific version installed
2. idempotent rollbacks
3. idempotent upgrades to a specific version (maybe not latest)