feat: Add ONNX & OpenVINO backend support, and torch dtype kwargs in Sentence Transformers Components

[lbux]

Related Issues

• fixes Sentence Transformers components do not support ONNX or OpenVINO formats #8802

Proposed Changes:

Sentence Transformer based components now expose a backend parameter that allows the user to specify a different backend besides the default of torch. Supported backends are onnx and openvino. Documentation for these backends can be found here.

How did you test it?

Integration tests were added for each of the supported backends. I am making this PR early on to have the CI assist with some tests as I can not run them locally.

Notes for the reviewer

• There is a major dependency conflict in the test environment. We can not install both the onnx and openvino backends at the same time due to a limitation with optimum-intel[openvino]==1.21.0 which does not support transformers>=4.47. The next optimum-intel update should add support for transformers>=4.47. For now, openvino tests are skipped.
• I am looking into implementing explicit onnx-gpu support
• I am looking into also implementing the changes into the SentenceTransformersDiversityRanker
• I am going to add tests to support torch dtype quantization

Checklist

• I have read the contributors guidelines and the code of conduct
• I have updated the related issue with new insights and changes
• I added unit tests and updated the docstrings
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test: and added ! in case the PR includes breaking changes.
• I documented my code
• I ran pre-commit hooks and fixed any issue

[coveralls]

Pull Request Test Coverage Report for Build 13171208202

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 12 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.008%) to 91.308%

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Files with Coverage Reduction	New Missed Lines	%
components/embedders/sentence_transformers_document_embedder.py	2	96.83%
components/embedders/sentence_transformers_text_embedder.py	2	96.36%
components/rankers/sentence_transformers_diversity.py	8	94.84%

Totals
Change from base Build 13161624824:	0.008%
Covered Lines:	8982
Relevant Lines:	9837

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💛 - Coveralls

[lbux]

Current failing tests are due to #8811. PR is still WIP but the tests pass locally.

[anakin87]

@lbux to fix failing tests, try doing something similar to #8809. It should work....