Middleware: Lambda Extensions (secrets)

[willfarrell]

This pattern can improve cold start times.

https://aws.amazon.com/blogs/compute/using-the-aws-parameter-and-secrets-lambda-extension-to-cache-parameters-and-secrets/
https://aws.amazon.com/blogs/compute/securely-retrieving-secrets-with-aws-lambda/

layers: https://docs.aws.amazon.com/systems-manager/latest/userguide/ps-integration-lambda-extensions.html

sample extensions: https://github.com/aws-samples/aws-lambda-extensions

Ref: https://www.youtube.com/watch?v=jYbfQ07Z7rM

[willfarrell]

I opened a PR, but need some help from someone that has used this lambda extension.

#1270