feat(rds): support backtrackWindow in DatabaseCluster (#17160)

This is a small PR to fix #9369 without needing to use an escape hatch.

Fixes  #9369

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-rds/lib/cluster.ts

@@ -40,6 +40,16 @@ interface DatabaseClusterBaseProps {
    */
   readonly instanceProps: InstanceProps;
 
+  /**
+   * The number of seconds to set a cluster's target backtrack window to.
+   * This feature is only supported by the Aurora MySQL database engine and
+   * cannot be enabled on existing clusters.
+   *
+   * @see https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/AuroraMySQL.Managing.Backtrack.html
+   * @default 0 seconds (no backtrack)
+   */
+  readonly backtrackWindow?: Duration
+
   /**
    * Backup settings
    *
@@ -364,6 +374,7 @@ abstract class DatabaseClusterNew extends DatabaseClusterBase {
       deletionProtection: defaultDeletionProtection(props.deletionProtection, props.removalPolicy),
       enableIamDatabaseAuthentication: props.iamAuthentication,
       // Admin
+      backtrackWindow: props.backtrackWindow?.toSeconds(),
       backupRetentionPeriod: props.backup?.retention?.toDays(),
       preferredBackupWindow: props.backup?.preferredWindow,
       preferredMaintenanceWindow: props.preferredMaintenanceWindow,

packages/@aws-cdk/aws-rds/test/cluster.test.ts

@@ -2032,6 +2032,26 @@ describe('cluster', () => {
       CopyTagsToSnapshot: true,
     });
   });
+
+  test('cluster has BacktrackWindow in seconds', () => {
+    // GIVEN
+    const stack = testStack();
+    const vpc = new ec2.Vpc(stack, 'VPC');
+
+    // WHEN
+    new DatabaseCluster(stack, 'Database', {
+      engine: DatabaseClusterEngine.AURORA,
+      instanceProps: {
+        vpc,
+      },
+      backtrackWindow: cdk.Duration.days(1),
+    });
+
+    // THEN
+    expect(stack).toHaveResourceLike('AWS::RDS::DBCluster', {
+      BacktrackWindow: 24 * 60 * 60,
+    });
+  });
 });
 
 test.each([