QOI in Luau

A QOI image de-/encoder for fast and lossless compression in Luau, for Roblox.

Why?

• This de-/encoder is stupidly simple, yet elegant; despite being less than 300 lines of code, it can compress images down to 50~20% of it's original size and decompress losslessly.
• Encodes and decodes in less that a second.
• Useful for saving the data of large EditableImages in DataStores.

I can't actually make comparisions of anykind to stb_image nor PNG, as there are no possible ways of benchmarking against the other algorithms within Roblox.

More info about the format at https://qoiformat.org.

More info about this implementation at https://devforum.roblox.com/t/2921027.