federated deployment toggle has dependency of TLS enablement

[msherman64]

The current default configuration for federation depends on the following values in defaults.yml

To enable federation, the current defaults must be set:

kolla_enable_tls_external: yes
kolla_external_fqdn: <cert is present and resolves to this fqdn>

If tls is disabled for example, the install will fail with cryptic errors

[msherman64]

There are two dependencies: The kolla-ansible error messages are largely resolved in ChameleonCloud/kolla-ansible#18 .

However, keycloak requires the endpoint to have a valid TLS cert for redirects to work.

A fix here would be to WARN and disable keystone federation if a certificate is not present, so that admin login would still be functional.