Add new MCP tools for knowledge management

[whitmo]

This PR adds four new MCP tools to enhance knowledge management capabilities:

• delete_knowledge_entry: Allows deletion of knowledge entries from the vector store
• update_knowledge_entry: Enables updating existing knowledge entries
• list_collections: Provides a list of available collections in the vector store
• create_collection: Allows creation of new collections with configurable vector size

These additions align with the project's next steps outlined in the documentation, particularly in the 'Knowledge Management Features' and 'Vector Store Operations' sections.