Godot 4: Use LiteDB NoSQL, Part 1

With the SQLite plugin unavailable for Godot 4 (temporarily), implement LiteDB for storing game data in GDScript & C#. Single file database, so no need to implement a full server-based database.

LiteDB page: https://www.litedb.org/
LiteDB NuGet package page: https://www.nuget.org/packages/LiteDB
LiteDB Studio: https://github.com/mbdavid/LiteDB.Studio/tree/master/LiteDB.Studio