Created typed class pin result in keyguard

* The initial goal was to remove PhoneConstants.
But in doing so, it made sense to replace an int[] array as a
return type with a strongly typed class called PinResult.
* In this push, the @SystemAPI is being defined.
The modification to keyguard will come in a following commit.

Bug: 147854704
Test: make
Merged-In: I0d1354fadda4143260f377ff8ff868b99b9c53d8
Change-Id: I0d1354fadda4143260f377ff8ff868b99b9c53d8