[iOS] Settings management vs UI split - KMEI vs main app

For the current implementation of the new Settings menu and management, the division of elements between KMEI and the Keyman for iOS app isn't what it should be.

Should a third-party app wish to utilize the new settings, that app should provide its own UI for this; KMEI should simply provide the tools necessary for settings management.

However, literally all of the new Settings code - both management _and_ UI - are implemented in KMEI. The actual UI we've implemented should instead reside within the main app's code.