Move uinput logic out of jni

The business logic should never reside in jni. The jni layer should only
be a pass-through from java to native.

In this CL, the business logic dealing with the creation of virtual
input devices is moved out of jni code and into native libinput code.

Bug: 335496563
Test: build
Flag: EXEMPT refactor
Change-Id: I907bccd9914fed6513f03c9bdaa658e4bc53e39b