Add TunerTimeFilter/Lnb interface and add openLnb in TunerService

Note that this CL also does some clean up on the namespace of
TunerService and TunerFrontend.

Also replaced the ITuner with IFrontend in TunerFrontend.

Test: make
Bug: 159067322
Change-Id: I3d32511a20b69b323331471c222762aa306a8eab