Wrap XCFramework into a swift package, for Apple (iOS, macOS) distribution

[BPerlakiH]

Importing / adding the libkiwix library into iOS and macOS application could become a lot easier, by providing a swift package, which is a folder structure + manifest file that is wrapping up the current XCFramework output.

Details / how to can be found here:
https://blog.devgenius.io/xcframework-swiftpackagemanager-c03f4b1903d9
https://developer.apple.com/documentation/xcode/distributing-binary-frameworks-as-swift-packages

[kelson42]

It's important we use this opportunity to rename the whole package to "libkiwix" to be coherent with the rest.

[BPerlakiH]

We have tried the following setups:

• creating an SPM with .binaryTarget pointing to a remote zip (of the libkiwix framework), containing the module mapping headers
• creating an SPM locally with .binaryTarget wrapping a local copy of the libkiwix framework, containing the module mapping
  Non of the above seemed to compile properly with the main project.
  One suspicion, why this is, that SPM is not yet supporting cross language bridging (C++ / Objective-C) yet.
  There are swift community requests for this feature:
• https://github.com/apple/swift-package-manager/blob/main/Documentation/Design/PackageManagerCommunityProposal.md#system-library-access-with-module-maps
• https://github.com/apple/swift-package-manager/blob/main/Documentation/Design/PackageManagerCommunityProposal.md#support-for-other-languages

For these reasons we have decided not to use Swift Package Manager for integrating our XCFramework, as it is not yet fully supported in it's current form.

[kelson42]

I will keep the ticket open, this will be reassesed in a year.