Fix for "NSExpression function is forbidden" (#411)

* For iOS 15.5, refactor how MGL Expressions are defined. Fix for "NSExpression function is forbidden" #331

* Convert CI Scheme to TestPlan. Add CI-Expressions TestPlan (which skips tests unrelated to `NSExpression`)

* Update Swift & Objective-C sample Code for MGL Expressions.  Use these patterns for fixing unit tests.

* Update Swift sample code & documentation for MGL expressions.  Update API docs (.h) & online docs (HTML) with:  `make darwin-style-code && make idocument`

* Refresh developer documentation for:  build dependencies, running unit tests from the command line, and logging in C++.

* Mark certain unit tests as "Expected Failures":  Awaiting unit test refactoring for https://github.com/maplibre/maplibre-gl-native/issues/331

* Update to latest Xcode & iOS SDK. Update GitHub Action Runner Images from https://github.com/actions/runner-images

* For iOS 15.5, add "Expected Failure" for tests

* Skip failing test unrelated to NSExpressions

* Convert macOS project to use Test Plans

* Exclude previously failing Offline Storage test

* Refactor MGL Match expressions for macOS & iOS 15.5

* Refactor Unit Tests so that "Excluded Failures" work for both macOS 12 & iOS 15.5

* Refresh documentation on how to test for macOS from the command line

README.md

@@ -169,7 +169,12 @@ Please refer to [Mapbox Maps SDK for iOS](platform/ios/platform/ios/) for detail
 
 ```bash
 cd platform/ios
+# open macOS project in Xcode
+make xproj
+
+# build or test from the command line
 make xpackage
+make macos-test
 ```
 
 This produces a `Mapbox.framework` in the `platform/ios/build/macos/pkg/` folder.