Add combine publishers for all objects and types

[cbaker6]

Adding the publishers such as Future to all one-shot async calls, making Parse-Swift modernized and SwiftUI ready. All methods that are capable of “publishing” end with the word Publisher. This means that there are 3 ways to use most of the methods that send/receive info to a Parse Server: 1) sync, 2) async, and 3) publisher.

As far as usage, you use the added publishers just like any other Combine publisher. The thing to remember is that all of the push/pull methods like save, fetch, etc. are Futures, so they start their work as soon as you call them and will only publish one result when finished. Any new subscriptions to an already fulfilledFuture will produce the original result. This is different from the ParseLiveQuery Subscription which will keep publishing events/subscriptions as long as it’s not cancelled.

Combine currently isn't supported on Linux, but if/when it ever is the combine features will automatically be available for use. Linux devs can use the async/sync callbacks instead.

• All objects publishable
• All types publishable
• Testcases
• Some fixes to ParseUser.logout to make it more predictable
• Bring minimum deployment to the same level on Xcode, SPM, and Cocoapods, [.iOS(.v12), .macOS(.v10_13), .tvOS(.v12), .watchOS(.v5)]. If a developer wants to support an older platform, they should use the Parse-Obj-C SDK

Slightly breaking (compiler should suggest the correct fix):

• delete, deleteAll, passwordReset, and verificationEmail use to all return an ParseError. These have all been switched to return a Result<Void, ParseError> instead to match everything else. This is helpful, because Future expects a result enum anyways

[codecov]

Codecov Report

Merging #73 (9b4a35d) into main (48a871e) will increase coverage by 0.45%.
The diff coverage is 89.27%.

@@            Coverage Diff             @@
##             main      #73      +/-   ##
==========================================
+ Coverage   78.45%   78.91%   +0.45%     
==========================================
  Files          52       61       +9     
  Lines        4693     4870     +177     
==========================================
+ Hits         3682     3843     +161     
- Misses       1011     1027      +16     

Impacted Files	Coverage Δ
Sources/ParseSwift/API/BatchUtils.swift	100.00% <ø> (ø)
...Authentication/Protocols/ParseAuthentication.swift	72.63% <ø> (ø)
Sources/ParseSwift/LiveQuery/LiveQuerySocket.swift	61.40% <ø> (ø)
Sources/ParseSwift/LiveQuery/ParseLiveQuery.swift	74.61% <ø> (ø)
...t/LiveQuery/Protocols/ParseLiveQueryDelegate.swift	20.00% <ø> (ø)
Sources/ParseSwift/LiveQuery/Subscription.swift	67.27% <ø> (-18.67%)	⬇️
Sources/ParseSwift/Types/Query.swift	90.58% <ø> (-0.28%)	⬇️
...Swift/Authentication/Internal/ParseAnonymous.swift	80.00% <57.14%> (-6.96%)	⬇️
...rseSwift/Authentication/3rd Party/ParseApple.swift	75.64% <69.23%> (-3.21%)	⬇️
Sources/ParseSwift/Objects/ParseInstallation.swift	82.15% <76.47%> (-0.07%)	⬇️
... and 25 more

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[cbaker6]

@TomWFox can you review the docs? All of the added docs are SwiftUI docs.

The large number of line additions is mostly test code

[TomWFox]

Looks good!