The npm package langchain/community has been deprecated. The VoyageEmbeddings class 

must be migrated to the dedicated package langchain/mongodb.

This deprecation is not a blocker, users can still make use of the package, but we'd want to move it sooner than later to avoid confusion and churn.

Acceptance Criteria

• Move the file voyage.ts from langchain/community to a suitable location in langchain/mongo
• Move the related voyage test files 
• Ensure unit and integration tests pass for VoyageEmbeddings in the new repository
• Open a PR and ensure it's merged and released (work with the LangChain team )
• Update LangChain.js documentation to include Voyage in the list of embedding models. (documentation lives in this repository)