Code Refactoring for CommonName (opensearch-project#867)

In this pull request, I have refactored the code related to shared names in both AD and forecasting modules to CommonNames. Additionally, the previously used CommonName has been renamed to ADCommonName. For the Forecasting module, I have introduced new names in ForecastCommonNames.

Testing done:
* gradle build

Signed-off-by: Kaituo Li <[email protected]>

Author: kaituo

src/test/java/org/opensearch/ad/TestHelpers.java

@@ -1516,7 +1516,7 @@ public static ClusterState createClusterState() {
 
         mappings
             .put(
-                    CommonName.JOB_INDEX,
+                CommonName.JOB_INDEX,
                 IndexMetadata
                     .builder("test")
                     .settings(

src/test/java/org/opensearch/ad/feature/SearchFeatureDaoParamTests.java

@@ -55,7 +55,6 @@
 import org.opensearch.ad.AnomalyDetectorPlugin;
 import org.opensearch.ad.NodeStateManager;
 import org.opensearch.ad.constant.ADCommonName;
-import org.opensearch.ad.constant.CommonName;
 import org.opensearch.ad.dataprocessor.Interpolator;
 import org.opensearch.ad.dataprocessor.LinearUniformInterpolator;
 import org.opensearch.ad.dataprocessor.SingleFeatureLinearUniformInterpolator;

src/test/java/org/opensearch/ad/transport/DeleteAnomalyDetectorTests.java

@@ -200,7 +200,7 @@ private ClusterState createClusterState() {
         Map<String, IndexMetadata> immutableOpenMap = new HashMap<>();
         immutableOpenMap
             .put(
-                    CommonName.JOB_INDEX,
+                CommonName.JOB_INDEX,
                 IndexMetadata
                     .builder("test")
                     .settings(