[iOS] Enable ad-hoc installation of KMPs shared via iTunes (and iCloud?)

Apparently JacobB intended to do this (and set the UIFileSharingEnabled flag to true in info.plist, which ultimately led to Apple rejecting the app) but then the work was jettisoned. It is fairly low priority, because other more generally useful ways of ad-hoc sharing (e.g., downloading from a website) work. But it would be nice for iOS users who have a Mac to be able to share via iTunes. Here are a couple sites I looked at in order to understand how this is supposed to work:
[This is where Apple describes how iTunes-based sharing works](https://support.apple.com/en-us/HT201301)
[This is a tutorial on how to hook up the plumbing in code](https://www.raywenderlich.com/1948/itunes-tutorial-for-ios-how-to-integrate-itunes-file-sharing-with-your-ios-app)