buffet: Add read-only properties with buffet config options

Added OemName, ModelName, ModelId, Name, Description, Location buffet
properties.
Added UpdateDeviceInfo to allow changing of device Name, Description and
Location.

BUG=brillo:377
TEST=FEATURE=test emerge-gizmo buffet
     test_that -b $BOARD $DEV_HOST buffet_BasicDBusAPI
CQ-DEPEND=CL:266217

Change-Id: Id27f9a65194d4b7176196b599280fc4ada66eda2
Reviewed-on: https://chromium-review.googlesource.com/266206
Reviewed-by: Vitaly Buka <vitalybuka@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
Tested-by: Vitaly Buka <vitalybuka@chromium.org>
6 files changed
tree: 73eba49caeb9a900c287acab4ee5955d83ef22c9
  1. buffet/