Added RDS policy exception cdk_nag

Author: aws-samkool

lib/posit-db.ts

@@ -24,6 +24,12 @@ export class DbStack extends cdk.NestedStack {
         reason: 'Adds complexity and will break the solution without Kube restart. As a solution starter this is not required.'
       },
     ])
+    NagSuppressions.addStackSuppressions(this, [
+      {
+        id: 'AwsSolutions-RDS10',
+        reason: 'Conflicts with stack deletion.'
+      },
+    ])
     NagSuppressions.addStackSuppressions(this, [
       {
         id: 'AwsSolutions-RDS6',