Actually fixes https://github.com/TurboWarp/packager/issues/528https://github.com/TurboWarp/packager/pull/861 fixed running large projects
in Chrome, but packaging still used string concatenation so it remained broken.
Now the concatenation part is done using TextEncoder & Uint8Arrays and a
template tag function to keep it readable.
This time I have actually tested it with a 1.0GB sb3.
Breaking Node API change: The data property returned by Packager#package() is
now always a Uint8Array instead of sometimes string and sometimes ArrayBuffer.
GarboMuffin