Emit build operation progress events for logging output (#4537)* Tweak BuildOperationListener#progress api* Use build operation id to reference progress* Add workaround for tracing log output via build operation progress for composite builds* Replace some Object typing of operation identifiers with OperationIdentifier.* Associate all progress logging with the current build operation.* Update logic to accommodate for all progress events now having build operation IDs.* Don't allow ProgressStartEvent.buildOperationCategory to be null.** Default it to uncategorized.