Configure secrets for identity providers

With component version v2.3, secrets can stored in Vault and be referenced by name.

Configure openshift4_authentication.secrets as following:

parameters:
  openshift4_authentication:
    secrets:
      company-keycloak: (1)
        clientSecret: '?{vaultkv:${cluster:tenant}/${cluster:name}/...}' (2)

1	This will be the `metadata.name` of the Secret in Kubernetes.
2	In this example `clientSecret` is a key that goes into the `stringData` of the Secret.

See Supported identity providers how to configure secret keys for various providers.

See Configure OIDC provider for an example how to reference such secrets.