Separate BlockMetaLogger file to a per-Chunk solution

[Zazsona]

At the moment, DecorHeads stores a single JSON file for tracking placed head data. Inevitably, as this file grows read/write operations will become more taxing.

The preposition is to separate this file on a per-chunk basis. This comes with two benefits:

1. Smaller files with limited scope
2. Files can be stored with the world, making them transfer-compatible, and removing the need to clean-up when the world is reset

Requirements:

• Knowledge of Minecraft world file structure, including the chunk calculation maths
• Supporting the legacy file (ideally transforming it to the proposed structure)