Revise Node class for better integration with Comptox AI Neo4j data

[yunchae-kim]

The current implementation of the Node class is inadequate and lacks complete functionality. In order to seamlessly interact with the Comptox AI Neo4j database, it's essential that we redesign and implement a more robust Node class.

Objectives:

1. Modularity: Design the Node class to be modular. This will ensure it efficiently handles different types of graph data, including node labels, relationships, and properties.
2. Extensibility: The class should serve as a foundational layer that can be easily extended. This will pave the way for future subclasses like Chemical, facilitating the inclusion of more specific node formats as needed.

Key Features to Implement:

• Robust methods to manage node properties.
• Ability to handle diverse node labels and relationships.
• Seamless integration capabilities with the Neo4j database.
• A clear structure that allows for easy subclassing for specific node types, such as Chemical.