Renew external access-token only for VAULT and KEYCLOAK

Current Situation

When the login is executed a thread is started that checks, whether the external access token coming from vault or Keycloak has to be renewed. This thread is always started but has only an effect when an active session for Keycloak or Vault exists.

Desired Behavior

The thread to renew an external access-token should only be executed, when Keycloak is involved.

As Vault is deprecated, the change only considers Keycloak since 2.7.0