Add "component" property to command instance

When sending commands, we'll use "component" to route the command to
the target component it was designated for.

As a temporary stop-gap, use "device" as the component name before
we have full implementation of component/trait schema model.

Also removed CommandDictionary from CommandInstance::FromJson since
the validation will be done outside of JSON parsing code in the future
Component Manager class.

BUG: 25841719
Change-Id: I5c649c257fb48ecaaedc1ced84931009f94c2bb3
Reviewed-on: https://weave-review.googlesource.com/1764
Reviewed-by: Vitaly Buka <vitalybuka@google.com>
14 files changed