Add a setup overlay for AOSP emulators.

Emulators have SetupWizard turned off by default.
The setup overlay provides the correct configs needed
to enable SetupWizard usage in an emulator. The emulator
build will need to have both the SetupWizard APK and the
product package overlay, e.g.:
PRODUCT_PACKAGE_OVEFRLAYS += \
    device/generic/car/setup/overlay
This product package overlay should precede other overlays
for emulators in makefile inclusion.

Bug: 148489116
Test: create an emulator build with the SUW APK + this overlay
Signed-off-by: Julius D'souza <jdsouza@google.com>
Change-Id: I53b8f073d6ab51c9c3c0a92fb21bf14d3559faa3