Pack Lua files into a single zip and load

[Jerboa-app]

• [x] packer
• [x] unpacker
• [x] https://github.com/nlohmann/json JSON for packing assets?
• [x] package.loaders https://stackoverflow.com/questions/18965489/lua-require-but-files-are-only-in-memory
• [x] test using the custom Lua loader