display: Clean up binder interface

The current binder implementation is inflexible when it comes to
adding new input/output parameters. It also needs a lot of
boilerplate code written when adding a simple enable/disable type
command.

Instead, let clients specify the parcels they want to pass and
unparcel them at the end points only.
Please note that it is assumed that all commands coming in
need the same permission checks. If this is no longer the case,
some commands need to be split out on the receiver end in
IQService.cpp.
This change also simplifies the code end clients need to write.
They should be able to include QServiceUtils and call a single
function to set the binder up and make the call.

Change-Id: I4db66f2427ecf16d7a6264462ae85815217a16b1