[ios, macos] Update minimum deployment versions to iOS 9, macOS 10.11 (#11776)

* [ios] Remove iOS 8 conditionals

* [ios, macos] Bump pod deployment targets

* [ios, macos] Add changelog entries

* [ios, macos] Update docs

* Remove unnecessary selector-based version checks

* Update SQLite note

* [ios, macos] Replace lightweight generics macros with direct use
   Lightweight generics for Foundation collections are available everywhere with the bump to iOS 9 and macOS 10.11.

* Update deprecated macOS method

platform/ios/Mapbox-iOS-SDK.podspec

@@ -20,7 +20,7 @@ Pod::Spec.new do |m|
   }
 
   m.platform              = :ios
-  m.ios.deployment_target = '8.0'
+  m.ios.deployment_target = '9.0'
 
   m.requires_arc = true