The main scripts for MinMicroG installer.

The recovery or Magisk Manager execute `update-binary`, which unzips and
executes defconf from the zip's root directory, and... does stuff. I hope to
have better docs about it someday, but for now, I've made sure you won't have
to deal with it even if you want to make a new pack. I've also tried to keep it
simple and readable, even if I failed miserably in several places.