change the Thread Network HAL api from 'reset' to 'hardwareReset'

This CL changes the API from 'reset' to 'hardwareReset' to make the
the definition of the API clearer. This CL also optimizes the Thread
Network HAL default implementation.

Bug: 289867661
Test: Run Thread stack on cuttlefish.
Change-Id: Id742453d9d7a0d369ac8f16905efdacfcfba1dbc