Update API: initial support

Initial pieces of the Update API callback framework.

- move the status callback params to a new object, UpdateEngineStatus to
allow for the easier addition of new params in the future.
- switch the IUpdateEngineStatusCallback to provide a
ParcelableUpdateEngineStatus instead of a series of individual params
- move the various GetStatus() methods to use the UpdateEngineStatus
object instead of a series of params (which will need future expansion)
- Add current and new product/os versions to both the UpdateEngineStatus
and the ParcelableUpdateEngineStatus.

Bug: 64808702
Test: unit tests, and performing OTAs via a test app calling
  IUpdateEngine::AttemptUpdate() via UpdateManager::performUpdateNow()

Change-Id: I53f66f3511049f0809855814e1e758023cd8cc08
(cherry picked from commit 4f96ebf85022837603f2e10100a044d234b7d86f)