wifi(implementation): Callback death handler

Add a new utility to handle callback death notifications. The new class
HidlCallbackHandler will be used by all the HIDL interface objects to
manage callbacks. Any dead clients will automatically removed from the
cb list by the utility class.

Bug: 34840719
Test: Compiles
Test: Verified that the cbs are deleted on crashing the framework
manually
Change-Id: I0f7ba8b3ed717c2e8e8fbf744a2501d0ad2d48c8