Refactor ADTask and Related Components

This PR includes several key refactoring changes:
- Extracts common code from ADTask into TimeSeriesTask, creating ForecastTask for forecasting-specific logic.
- Consolidates common code from ADTaskType into TaskType and introduces ForecastTaskType for forecasting-related purposes.
- Renames ADTaskState to TaskState for consistent code reuse.
- Renames the method getId in ADTask to getConfigId to differentiate it from other IDs like task id.

Testing done:
1. Added unit tests for the new code to ensure functionality.
2. Executed a successful Gradle build.

Signed-off-by: Kaituo Li <kaituo@amazon.com>

src/main/java/org/opensearch/ad/AnomalyDetectorJobRunner.java

@@ -32,7 +32,6 @@
 import org.opensearch.action.index.IndexRequest;
 import org.opensearch.action.support.WriteRequest;
 import org.opensearch.ad.indices.ADIndexManagement;
-import org.opensearch.ad.model.ADTaskState;
 import org.opensearch.ad.model.AnomalyDetector;
 import org.opensearch.ad.settings.AnomalyDetectorSettings;
 import org.opensearch.ad.task.ADTaskManager;
@@ -64,6 +63,7 @@
 import org.opensearch.timeseries.constant.CommonName;
 import org.opensearch.timeseries.function.ExecutorFunction;
 import org.opensearch.timeseries.model.Job;
+import org.opensearch.timeseries.model.TaskState;
 import org.opensearch.timeseries.util.SecurityUtil;
 
 import com.google.common.base.Throwables;
@@ -509,7 +509,7 @@ private void stopAdJobForEndRunException(
                 executionStartTime,
                 error,
                 true,
-                ADTaskState.STOPPED.name(),
+                TaskState.STOPPED.name(),
                 recorder,
                 detector
             )

src/main/java/org/opensearch/ad/cluster/ADDataMigrator.java

@@ -15,9 +15,9 @@
 import static org.opensearch.ad.model.ADTask.DETECTOR_ID_FIELD;
 import static org.opensearch.ad.model.ADTask.IS_LATEST_FIELD;
 import static org.opensearch.ad.model.ADTask.TASK_TYPE_FIELD;
-import static org.opensearch.ad.model.ADTaskType.taskTypeToString;
 import static org.opensearch.ad.settings.AnomalyDetectorSettings.MAX_DETECTOR_UPPER_LIMIT;
 import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
+import static org.opensearch.timeseries.model.TaskType.taskTypeToString;
 import static org.opensearch.timeseries.util.RestHandlerUtils.XCONTENT_WITH_TYPE;
 import static org.opensearch.timeseries.util.RestHandlerUtils.createXContentParserFromRegistry;
 
@@ -39,7 +39,6 @@
 import org.opensearch.ad.constant.ADCommonName;
 import org.opensearch.ad.indices.ADIndexManagement;
 import org.opensearch.ad.model.ADTask;
-import org.opensearch.ad.model.ADTaskState;
 import org.opensearch.ad.model.ADTaskType;
 import org.opensearch.ad.model.AnomalyDetector;
 import org.opensearch.ad.model.DetectorInternalState;
@@ -59,6 +58,7 @@
 import org.opensearch.timeseries.constant.CommonName;
 import org.opensearch.timeseries.function.ExecutorFunction;
 import org.opensearch.timeseries.model.Job;
+import org.opensearch.timeseries.model.TaskState;
 import org.opensearch.timeseries.util.ExceptionUtil;
 
 /**
@@ -245,15 +245,15 @@ private void createRealtimeADTask(Job job, String error, ConcurrentLinkedQueue<J
                     Instant now = Instant.now();
                     String userName = job.getUser() != null ? job.getUser().getName() : null;
                     ADTask adTask = new ADTask.Builder()
-                        .detectorId(detector.getId())
+                        .configId(detector.getId())
                         .detector(detector)
                         .error(error)
                         .isLatest(true)
                         .taskType(taskType.name())
                         .executionStartTime(now)
                         .taskProgress(0.0f)
                         .initProgress(0.0f)
-                        .state(ADTaskState.CREATED.name())
+                        .state(TaskState.CREATED.name())
                         .lastUpdateTime(now)
                         .startedBy(userName)
                         .coordinatingNode(null)