[Java] PTransform that integrates Cloud AI Prediction functionality

The goal is to create a PTransform that integrates Google Cloud AI Platform Prediction functionality [1] for Java SDK. The transform should work both in batch and streaming mode.

One possible solution is to utilize a `tfx_bsl` library [2] which offers a `RunInference` Beam's PTransform[2] able to get predictions from Google Cloud AI Platform Prediction via cross-language. 

[1] https://cloud.google.com/ai-platform/prediction/docs/
[2] https://github.com/tensorflow/tfx-bsl/blob/ecec31b2152fc73f4c26f5a5db86173cfcf25c99/tfx_bsl/beam/run_inference.py#L99