doc(quickstart): add IoT

Author: muneebahmed10

README.quickstart.cloud9.md

@@ -13,6 +13,7 @@ See [Get help](#get-help) for support.
     -   CloudFormation stacks
     -   [CloudWatch Logs](https://docs.aws.amazon.com/cloud9/latest/user-guide/cloudwatch-logs-toolkit.html)
     -   ECR
+    -   IoT explorer
     -   Lambda functions
     -   S3 explorer
 -   [AWS Serverless Applications (SAM)](#sam-and-lambda)

README.quickstart.vscode.md

@@ -14,6 +14,7 @@ See [Setup](#additional-setup-steps) for installation requirements, or [Get help
     -   CloudWatch Logs
     -   ECR
     -   EventBridge schemas
+    -   [IoT explorer](https://docs.aws.amazon.com/toolkit-for-vscode/latest/userguide/iot-start.html)
     -   Lambda functions
     -   S3 explorer
     -   Step Functions