[WIP] Add new plugin : Genkit HNSW

[retzd-tech]

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This pull request is related to:

• [ ] A bug
• [x] A new feature
• [x] Documentation
• [ ] Other (please specify)

I have checked the following:

• [x] I have read and understood the contribution guidelines and the code of conduct;
• [x] I have added new tests (for bug fixes/features);
• [x] I have added/updated the documentation (for bug fixes / features).

Description: Add a new plugin Genkit HNSW