Release 0.8.0

• Configuration and model for DRCD (Chinese SQUAD) based on Chinese BERT
• Remove all Keras usage in favor of tensorflow.keras
• Start refactoring of goal-oriented bot code
• Update dependencies versions
• Add a BERT-embedding component as a first step of moving from google-research/bert to HuggingFace's Transformers
• Release BERT-based sentence embedders models
• Smaller changes and fixes