[AWARE] Make PeerHandle parcelable

PeerHandle is an opaque object used to represent a peer for
communication and data-path setup.

Applications which use multiple components may want to communicate the
PeerHandle across components using Binder - requiring a Parcelable
implementation.

Bug: 119594815
Test: All Wi-Fi Manager unit tests + added unit test for this CL
Change-Id: Iae1c8c223677d232c54e7f6c2bdf811764ab6c82