Fixes SPM support from 1.7.0 version

[caggiulio]

Motivation and Context

This PR fixes the support for Swift Package Manager (SPM).
To enable SPM compatibility, several structural adjustments were necessary:

1. Split Objective-C and Swift files into separate folders
   SPM does not support mixing Objective-C and Swift files within the same target. Therefore, Objective-C and Swift sources have been reorganized into distinct directories.

2. Refactor of the Package file

3. Fixes import of Swift interop generated headers

4. Small import fixes

Important

The branch starts from 1.7.0 version. As agreed in the LinkedIn chat, we opened the PR towards master branch, so you can manage the 1.8.0 release.

[mokagio]

@pmusolino @caggiulio I'd say this PR can now be closed given the 2.0.0 release with full SwiftPM support? https://github.com/pmusolino/Wormholy/releases/tag/2.0.0

I just added it to WooCommerce iOS and it works as expected.

Thanks to you both.

[pmusolino]

Hey @mokagio 👋 The plan is to merge this PR into a different branch because the new version 2.0 requires at least iOS 16.

PS: in the PR of WooCommerce you mentioned, there is a question regarding including it just in debug. Please, take a look at this comment #144 (comment)

[caggiulio]

Hey @mokagio 👋 The plan is to merge this PR into a different branch because the new version 2.0 requires at least iOS 16.

PS: in the PR of WooCommerce you mentioned, there is a question regarding including it just in debug. Please, take a look at this comment #144 (comment)

Hi @pmusolino 👋 Thanks for the update!
Just a quick question — do you have an estimated timeline for when this merge might happen?
Looking forward to it, and thanks again for your work! 🙌