feat: [BackupDr] Add support for AlloyDB backup and restore (#8884)

* feat: Add support for AlloyDB backup and restore
docs: A comment for field `log_retention_days` in message `.google.cloud.backupdr.v1.BackupPlan` is changed

PiperOrigin-RevId: 862089230

Source-Link: googleapis/googleapis@4b64cb4

Source-Link: googleapis/googleapis-gen@ee74e8b
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BackupDr/metadata/V1/Backupvault.php

@@ -358,6 +358,25 @@ public static function backupVaultName(string $project, string $location, string
         ]);
     }
 
+    /**
+     * Formats a string containing the fully-qualified path to represent a cluster
+     * resource.
+     *
+     * @param string $project
+     * @param string $location
+     * @param string $cluster
+     *
+     * @return string The formatted cluster resource.
+     */
+    public static function clusterName(string $project, string $location, string $cluster): string
+    {
+        return self::getPathTemplate('cluster')->render([
+            'project' => $project,
+            'location' => $location,
+            'cluster' => $cluster,
+        ]);
+    }
+
     /**
      * Formats a string containing the fully-qualified path to represent a crypto_key
      * resource.
@@ -535,6 +554,7 @@ public static function storagePoolName(string $project, string $zone, string $st
      * - backupPlanAssociation: projects/{project}/locations/{location}/backupPlanAssociations/{backup_plan_association}
      * - backupPlanRevision: projects/{project}/locations/{location}/backupPlans/{backup_plan}/revisions/{revision}
      * - backupVault: projects/{project}/locations/{location}/backupVaults/{backupvault}
+     * - cluster: projects/{project}/locations/{location}/clusters/{cluster}
      * - cryptoKey: projects/{project}/locations/{location}/keyRings/{ring}/cryptoKeys/{key}
      * - cryptoKeyVersion: projects/{project}/locations/{location}/keyRings/{key_ring}/cryptoKeys/{crypto_key}/cryptoKeyVersions/{crypto_key_version}
      * - dataSource: projects/{project}/locations/{location}/backupVaults/{backupvault}/dataSources/{datasource}