Better Statistics Screen

General changelog

• Added icons to tabs' names, for decorative purposes.
• Added .nbt file support. Save and load statistics files in NBT format.
• Added support for external file drag-and-dropping. Drop files from your desktop or file explorer, into the better Statistics screen.

Technical changelog

• Refactored translation key names.

API changelog

• A lot of code refactoring. Expect breaking changes if you use the APIs.
• McbsFile migrated from using JSON code for serialization, to instead using Mojang's Codec<T> system.
• BClientRegistries migrated from using simple Map<K, V>s, to instead using the game's Registry<V> system.