Introduce emulation of i8042 device to allow the guest to stop the
VM by issuing a reset event.
The device has been copied over from the Crosvm code base, relying on
the commit 0268e26e1ac9e09aa51d733482c5df139cd8d588.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>