Introduce "input_id" column to the channels table

Until now, TvInputService has been providing the channels. But from now
on, a TvInputService can have several TV inputs and the TV input will
provide its channels.
So introduced "input_id" which is the ID of the TV input instead of
"service_name" which designates the TvInputService.
Also updated related APIs.

BUG: 16138420
Change-Id: I1d4dcad17c028384ab75a7f71ee0b305509ae952