Add Disconnected registry option

[mbach04]

Extend Faros to allow users to specify a local registry where OCP images are already mirrored.

1. Adds new TUI Var local_registry_hostname
2. Adds new var openshift_installer_local_registry_hostname to install-config template

Note: local_registry_hostname assumes hostname + port myregistry.local:5000

[mbach04]

Doesn't appear to be an actual Linting issue, but something in the linter is misconfigured / failing.