Add support of Components/Traits to local privet APIs Added support for new privet APIs /privet/v3/traits and /privet/v3/components to obtain the full trait/component trees as well as expanded the existing /privet/v3/checkForUpdates to include the component/trait fingerprints. BUG: 25917521 Change-Id: Ib753817f88f611935057ca7bd1a1bf02addfb69c Reviewed-on: https://weave-review.googlesource.com/1791 Reviewed-by: Vitaly Buka <vitalybuka@google.com>