Add CloudWatch Synthetics Canary in gboost create template repo

[bestickley]

• Add basic initial test to user who is just creating demo can understand how canaries work
• Create custom Node.js Canary Script: https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch_Synthetics_Canaries_WritingCanary_Nodejs.html
• Utilize data-test attributes for selectors
• Remember you can use entire aws-sdk within canary scripts
• Rollback deployment if canary fails: https://www.youtube.com/watch?v=DUIdbs_8AZA
• Will also need to integrate CodeDeploy within pipeline, maybe create another issue?
• Use CodeDeploy postHook. Docs: https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_codedeploy-readme.html#pre-and-post-hooks

Maybe we don't need to use CloudWatch Synthetics? We can just pass lambda with puppeteer bundled to codedeploy? Not sure how to integrate. Synthetics is nice to integrate with X-Ray to see on your service map though... Need to research. See: https://docs.aws.amazon.com/cdk/api/v2/docs/aws-synthetics-alpha-readme.html