Feature: Add Document Retrieval with Metadata Filtering

[cedrickrusche]

This pull request introduces the methods get and aget like in ChromaDB to retrieve data by metadata.

🔧 Changes

• Asynchronous Document Retrieval: Implemented the aget method to asynchronously retrieve documents based on optional filters and parameters.
• Synchronous Document Retrieval: Added the get method for synchronous document retrieval, leveraging the asynchronous aget method.
• Metadata Filtering: Created the __query_collection_with_filter method to support filtering conditions in the SQL WHERE clause without similarity function
• Test Cases: Added unit tests for both asynchronous and synchronous document retrieval methods to ensure functionality and reliability.

📈 Impact

These changes let us retrieve the current content to get insights about the data in the database e.g. to find outdated content.