Expose a credentials reference in VideoPickerValue

[abjerner]

If we later need to fetch additional information about a saved video, we may need to also save a reference to the credentials that were originally used for fetching the video.

Normally an instance of VideoPickerValue would be serialized as:

{
  "provider": {
    "alias": "providerAlias",
    "name": "Provider Name"
  },
  "details": { },
  "embed": { },
  "html": "..."
}

We already save a reference about the provider, but a single solutions may use multiple accounts (credentials) of a given provider.

Saving a reference to the credentials would help tracing back with credentials that were used for fetching the video details. Since we shouldn't save or expose any sensitive information about the credentials, the format could look something like this:

{
  "provider": {
    "alias": "providerAlias",
    "name": "Provider Name"
  },
  "credentials": {
    "id": "fda08a63-57a8-4eb2-8131-d5efb7cd0302"
  },
  "details": { },
  "embed": { },
  "html": "..."
}