[Remote Routing Table] Add write flow for remote routing table (opensearch-project#13870)

* Introduce RemoteRoutingTableService for shard routing table management

Signed-off-by: Himshikha Gupta <himshikh@amazon.com>
Co-authored-by: Bukhtawar Khan <bukhtawa@amazon.com>
Co-authored-by: Arpit Bandejiya <abandeji@amazon.com>

Author: 3 people

server/src/main/java/org/opensearch/gateway/remote/RemoteClusterStateService.java

@@ -172,6 +172,12 @@ public class RemoteClusterStateService implements Closeable {
     /**
      * Manifest format compatible with codec v2, where global metadata file is replaced with multiple metadata attribute files
      */
+    public static final ChecksumBlobStoreFormat<ClusterMetadataManifest> CLUSTER_METADATA_MANIFEST_FORMAT_V2 =
+        new ChecksumBlobStoreFormat<>("cluster-metadata-manifest", METADATA_MANIFEST_NAME_FORMAT, ClusterMetadataManifest::fromXContentV2);
+
+    /**
+     * Manifest format compatible with codec v3, where global metadata file is replaced with multiple metadata attribute files
+     */
     public static final ChecksumBlobStoreFormat<ClusterMetadataManifest> CLUSTER_METADATA_MANIFEST_FORMAT = new ChecksumBlobStoreFormat<>(
         "cluster-metadata-manifest",
         METADATA_MANIFEST_NAME_FORMAT,
@@ -1533,6 +1539,8 @@ private ChecksumBlobStoreFormat<ClusterMetadataManifest> getClusterMetadataManif
         long codecVersion = getManifestCodecVersion(fileName);
         if (codecVersion == MANIFEST_CURRENT_CODEC_VERSION) {
             return CLUSTER_METADATA_MANIFEST_FORMAT;
+        } else if (codecVersion == ClusterMetadataManifest.CODEC_V2) {
+            return CLUSTER_METADATA_MANIFEST_FORMAT_V2;
         } else if (codecVersion == ClusterMetadataManifest.CODEC_V1) {
             return CLUSTER_METADATA_MANIFEST_FORMAT_V1;
         } else if (codecVersion == ClusterMetadataManifest.CODEC_V0) {

server/src/test/java/org/opensearch/gateway/remote/ClusterMetadataManifestTests.java

@@ -539,6 +539,7 @@ public void testClusterMetadataManifestXContentV2WithoutEphemeral() throws IOExc
             "routing-path",
             InternalRemoteRoutingTableService.INDEX_ROUTING_METADATA_PREFIX
         );
+
         ClusterMetadataManifest originalManifest = ClusterMetadataManifest.builder()
             .clusterTerm(1L)
             .stateVersion(1L)