Move neuralnetworks HAL to hardware/interfaces

The neuralnetworks hal was placed in
frameworks/ml/nn/hardware/interfaces while VTS tests were being
developed.

This CL moves it to hardware/interfaces and another CL removes
it from frameworks/ml/nn/hardware/interfaces.

VTS tests included in a sibling CL in this topic.

Bug: 63905942
Test: mm -j40
Change-Id: I0e6c84de72a763edbaef3e9b3063c3ecca216337