Vector index support for Memgraph's integration

[matea16]

Hi! Memgraph recently introduced a vector search feature and I took the opportunity to update the integration with LlamaIndex by adding new capabilities :)

This PR enhances the Memgraph integration with LlamaIndex with several significant improvements and new functionalities:

1. Support for vector indices
   Added the ability to leverage vector indices in Memgraph using Memgraph's vector search
2. Optimized schema refresh
   Introduced the SHOW SCHEMA INFO; query to efficiently refresh and synchronize the schema during runtime. This reduces overhead and ensures up-to-date schema information without unnecessary latency.
3. Bug fixes for parameterized queries

Type of Change

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• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Your pull-request will likely not be merged unless it is covered by some form of impactful unit testing.

• I believe this change is already covered by existing unit tests

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[logan-markewich]

This looks pretty good. Thanks for updating tests.

Out of curiosity, there was a lot of changes to cypher queries. Is this a breaking change for users using the old code?

[matea16]

Hi @logan-markewich, thank you for being so quick with this! The cypher updates were mostly to improve some functionality, especially with parametrized queries so there shouldn't be any breaking changes, only fixes :)