Neuralnetworks HAL cleanup -- hardware/interfaces

Does three primary cleanups:
1) Removes unused OperandTypes, creates OEM types
2) Creates explicit ErrorStatus; functions return status
3) IDevice::initialize renamed to getCapabilities,
   IDevice::getSupportedSubgraph renamed to getSupportedOperations

Additionally fixes the corresponding VTS tests.

Bug: 63905942
Test: mm, vts
Change-Id: Ib4c61b9b13963ac2367f21dc3c20e5946eb955a9