Cognitive Services - Speaker Recognition

**Is your feature request related to a problem? Please describe.**
[Speaker Recognition](https://azure.microsoft.com/en-us/services/cognitive-services/speaker-recognition) is now available in preview. I'd like to be able to call this API using mmlspark.

**Describe the solution you'd like**
I'd like to be able to call the Speaker Recognition API using [mmlspark.cognitive](https://mmlspark.blob.core.windows.net/docs/1.0.0-rc1/pyspark/mmlspark.cognitive.html).

**Additional context**
Until this feature is developed, what is the best work around? Should I call the Speaker Recognition API using [HttpOnSpark](https://github.com/Azure/mmlspark/blob/master/notebooks/samples/HttpOnSpark%20-%20Working%20with%20Arbitrary%20Web%20APIs.ipynb)?

Please let me know if any additional info would be helpful.

AB#1984583

Start with the mmlspark.cognitive documentation linked in the issue and compare it with the HttpOnSpark sample notebook. Determine the intended Speaker Recognition API integration and how completion would be verified; the issue does not name implementation files or tests.

Written by the indexing model from the issue text.