Implement Dataflow pipeline to get code embeddings
This MR provides a Dataflow pipeline that can be run locally or remotely to get embeddings for the code completion obtained in https://gitlab.com/gitlab-org/modelops/applied-ml/code-suggestions/prompt-library/-/merge_requests/11.
README.md contains the description of the required steps to run this pipeline.
Closes https://gitlab.com/gitlab-org/modelops/applied-ml/code-suggestions/ai-assist/-/issues/184