Define more background tasks

* Each executor manages its own background task
* For attributed sessions, define another background task to send the session_time to update user (in addition to the existing request to the outcomes endpoint)

Author: nan-li

iOS_SDK/OneSignalSDK/OneSignalCore/Source/OneSignalCommonDefines.h

@@ -184,9 +184,13 @@ typedef enum {ATTRIBUTED, NOT_ATTRIBUTED} FocusAttributionState;
 #define focusAttributionStateString(enum) [@[@"ATTRIBUTED", @"NOT_ATTRIBUTED"] objectAtIndex:enum]
 
 // OneSignal Background Task Identifiers
-#define ATTRIBUTED_FOCUS_TASK           @"ATTRIBUTED_FOCUS_TASK"
-#define UNATTRIBUTED_FOCUS_TASK         @"UNATTRIBUTED_FOCUS_TASK"
-#define USER_MANAGER_BACKGROUND_TASK    @"USER_MANAGER_BACKGROUND_TASK"
+#define ATTRIBUTED_FOCUS_TASK                   @"ATTRIBUTED_FOCUS_TASK"
+#define UNATTRIBUTED_FOCUS_TASK                 @"UNATTRIBUTED_FOCUS_TASK"
+#define SEND_SESSION_TIME_TO_USER_TASK          @"SEND_SESSION_TIME_TO_USER_TASK"
+#define OPERATION_REPO_BACKGROUND_TASK          @"OPERATION_REPO_BACKGROUND_TASK"
+#define IDENTITY_EXECUTOR_BACKGROUND_TASK       @"IDENTITY_EXECUTOR_BACKGROUND_TASK_"
+#define PROPERTIES_EXECUTOR_BACKGROUND_TASK     @"PROPERTIES_EXECUTOR_BACKGROUND_TASK_"
+#define SUBSCRIPTION_EXECUTOR_BACKGROUND_TASK   @"SUBSCRIPTION_EXECUTOR_BACKGROUND_TASK_"
 
 // OneSignal constants
 #define OS_PUSH @"push"