Add Memgraph as graphdb vendor

[DavIvek]

Summary

This PR adds Memgraph as a graphdb vendor.

Type of Change

• [ ] Bug fix
• [x] New feature
• [ ] Performance improvement
• [ ] Documentation/Tests

Objective

The objective of this change is to add Memgraph as a supported graph database vendor in Graphiti. Memgraph is a high-performance, in-memory graph database that supports open Cypher queries and provides advanced features such as vector and text search, graph algorithms, and real-time analytics.

Testing

• [ ] Unit tests added/updated
• [ ] Integration tests added/updated
• [ ] All existing tests pass

Breaking Changes

• [ ] This PR contains breaking changes

If this is a breaking change, describe:

• What functionality is affected
• Migration path for existing users

Checklist

• [ ] Code follows project style guidelines (make lint passes)
• [ ] Self-review completed
• [ ] Documentation updated where necessary
• [ ] No secrets or sensitive information committed

Related Issues

Closes #[issue number]

[danielchalef]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[DavIvek]

I have read the CLA Document and I hereby sign the CLA

[vigneshnrfs]

Hi. How close are we to merging this feature? That would help a lot of folks.

[lifeinchords]

same here @vigneshnrfs, eagerly waiting for this ...