BREAKAGE: seed param moved from global configuration to registration endoint

[peppelinux]

this definitely closes
#60

now we have the seed parameter as a Registration endpoint internal parameter

    "registration": {
      "path": "registration",
      "class": "oidcop.oidc.registration.Registration",
      "kwargs": {
        "client_authn_method": None,
        "client_secret_expiration_time": 432000,
        "client_id_generator": {
           "class": 'oidcop.oidc.registration.random_client_id',
           "kwargs": {
                "seed": "that-optional-random-value"
           }
       }
      }
    },