support refresh service

[ilya-korotya]

w3.org description for this type https://www.w3.org/2018/credentials/v1

"refreshService": {
          "@id": "cred:refreshService",
          "@type": "@id",
          "@context": {
            "@version": 1.1,
            "@protected": true,

            "id": "@id",
            "type": "@type",

            "cred": "https://www.w3.org/2018/credentials#",

            "ManualRefreshService2018": "cred:ManualRefreshService2018"
          }
        },