Qdrant - refactor and release a major version

[anakin87]

important

• the embedding_field init parameter of QdrantDocumentStore will break things if not set to the default value ("embedding") -> should be removed
• the return_embedding init parameter of QdrantDocumentStore is not used and is confusing -> should be removed
  EDIT: I was wrong, it is used

nice to have

• set the default value for scale_score in Retrievers to False, as we do for all other retrievers
• separate well the tests for Document Store retrieval methods and Retrievers (non breaking)

[anakin87]

Also the init parameter duplicate_documents is not used and should be removed.

[anakin87]

done in #861 and #862

released a new major version of the package: https://pypi.org/project/qdrant-haystack/4.0.0/