Move subtype related utility class to utils package

java/src/com/android/inputmethod/keyboard/KeyboardId.java

...c/com/android/inputmethod/keyboard/KeyboardLayoutSet.java

...rc/com/android/inputmethod/keyboard/MainKeyboardView.java

...ndroid/inputmethod/keyboard/internal/KeyboardBuilder.java

...com/android/inputmethod/latin/RichInputMethodManager.java

java/src/com/android/inputmethod/latin/SubtypeSwitcher.java

...c/com/android/inputmethod/latin/UserBinaryDictionary.java

...inputmethod/latin/settings/AdditionalSubtypeSettings.java

.../src/com/android/inputmethod/latin/settings/Settings.java

.../android/inputmethod/latin/settings/SettingsFragment.java

...droid/inputmethod/latin/utils/AdditionalSubtypeUtils.java

...m/android/inputmethod/latin/utils/SubtypeLocaleUtils.java

...roid/inputmethod/latin/utils/SubtypeLocaleUtilsTests.java