Since we're using signals to connect to the Logger we don't need an
interface class, and the only thing still used was the log level enum.
Put those values in a dedicated header instead.
Change-Id: Ic3aee14ba13b81e283b477d11b1c15a5c26ffeab
We don't need this file, and the implementations are stubs, causing a
compile warning. Remove it from the build.
Change-Id: I4ee2594c8fbc3ecf4661cc4144f8d9072bd6d983
