Closes https://github.com/Unstructured-IO/unstructured/issues/1319,
closes https://github.com/Unstructured-IO/unstructured/issues/1372
This module:
- implements EmbeddingEncoder classes which track embedding related data
- implements embed_documents method which receives a list of Elements,
obtains embeddings for the text within Elements, updates the Elements
with an attribute named embeddings , and returns the updated Elements
- the module uses langchain to obtain the embeddings
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- The PR additionally fixes a JSON de-serialization issue on the
metadata fields.
To test the changes, run `examples/embed/example.py`
