Add TPC model for length of stay prediction

- Implement Temporal Pointwise Convolutional Networks (Rocheteau et al., CHIL 2021)
- Add comprehensive example with synthetic ICU data
- Add a comprehensive tcp_example note that show how to run the entire pipeline
- Full PyHealth integration with standard MSE loss

Author: levisstrauss

examples/tpc_example.ipynb

@@ -26,4 +26,5 @@
 from .transformer import Transformer, TransformerLayer
 from .transformers_model import TransformersModel
 from .vae import VAE
-from .sdoh import SdohClassifier
+from .sdoh import SdohClassifier
+from .tpc import TPC, TPCBlock