iOS-393 Move NYPLReachabilityManager class from Simplified-iOS repo

[ErnestFan]

What's this do?
Move NYPLReachabilityManager so it is accessible from NYPLAudiobookToolkit

Why are we doing this? (w/ JIRA link if applicable)
iOS-393

How should this be tested? / Do these changes have associated tests?
N/A

Dependencies for merging? Releasing to production?
N/A

Does this include changes that require a new SimplyE/Open eBooks build for QA?
N/A

Has the application documentation been updated for these changes?
N/A

Did someone actually run this code to verify it works?
@ErnestFan

[ErnestFan]

There is another related class NYPLReachability in Simplified-iOS repo, I didn't move that because that's for constantly monitoring the reachability status which is not needed for NYPLAudiobookToolkit. Also, it is a singleton so it's better not to expose it to every framework.

[ErnestFan]

@ettore The SPM unit tests failed because kSCNetworkReachabilityFlags is unavailable on mac-os.
I am thinking of updating the CI script, so the test is iOS-specific. However, swift test does not provide such option.
We will need to switch to xcodebuild in order to build and test, according to this article.
What's your thought on this?

[ettore]

@ettore The SPM unit tests failed because kSCNetworkReachabilityFlags is unavailable on mac-os.
I am thinking of updating the CI script, so the test is iOS-specific. However, swift test does not provide such option.
We will need to switch to xcodebuild in order to build and test, according to this article.
What's your thought on this?

I would try to not build the Reachability source file for macOS, since it doesn’t really make sense for the Mac. If should be possible to do so in the Package.swift, or i suppose we could just do it with a #ifdef.

[ErnestFan]

@ettore I added #if TARGET_OS_IPHONE and it now passes the unit test, thanks for the suggestion.

[ettore]

This is fine for now since we don't have macOS apps. But I want to make a correction about what I said last night. Reachability does make sense on macOS and it does look supported according to the docs (since macOS 10.6) so yeah, I am not sure why it won't compile. I wonder if it was some kind of SPM caching issue......