Make IInputMethodManager to oneway (6/N)

Create InputMethodSubtype and InputMethodSubtypeList
result callback and apply it to :

-. getLastInputMethodSubtype
-. getCurrentInputMethodSubtype
-. getEnabledInputMethodSubtypeList

Bug: 163453493
Test: Manual test with keyboard
Test: atest CtsInputMethodTestCases
Change-Id: I646ef4ae0570aae1812ea267f309441fdec6938d