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>
6 files changed