Reimplement AOSP's home-key behavior configuration

Add support for resource-based long-press and double-tap behaviors,
bringing back the functionality introduced by Google at change
I4564d9e4d127f782ed5bd8eb613ef8f2255176cc on top of our own
hardware key rebinding code

commit caca88150cc22a9324b6fed89ecdf394e68cf6f8
Author: Jeff Brown <jeffbrown@google.com>
Date:   Thu May 9 13:34:33 2013 -0700

    Support double-tap home to go to recents.

    Add config resources to enable the following behavior for
    certain devices:

    * press home - go home
    * long-press home - launch assist intent
    * double-tap home - open recents

    Bug: 8891502
    Change-Id: I4564d9e4d127f782ed5bd8eb613ef8f2255176cc
    (cherry picked from commit b7805698035622a633b2d76f7ca60169aaa9f0ca)

Change-Id: I578700abf8c51e613a4227cdf9f6c3bff90feec9