Unified BulkInference for TFX Pipeline

[ConfuzedCoder]

TFX is framework neutral and can be used with other non-TF ML frameworks but the current version of the bulkInference only supports the Tensorflow model, which limits the ability of TFX. I would like to enhance the buikInference so that it can support many other non-TF frameworks like PyTorch and Xgboost.