The /auth context path was used by legacy WildFly-based Keycloak but
is no longer needed for Quarkus-based Keycloak (17+) or RHBK. The
current default of /auth forces users to explicitly pass an empty
keycloak_context to avoid broken API URLs.
This changes the default to an empty string, updates argument_specs
and README documentation, and removes the now-unnecessary
keycloak_context: '' overrides from all molecule converge files.
Users on legacy WildFly-based Keycloak can still set
keycloak_context: /auth explicitly.
Made-with: Cursor
