Generic package

[apgrucza]

Added the ability to build a generic Lambda package. The Lambda function retrieves its parameters at runtime from the AWS Systems Manager Parameter Store and AWS Secrets Manager. Also added a Lambda package for rotation of the RSA keys.

GitHub does not show the differences in build/build.js very well. I suggest using a different tool to view the changes for this file.

Also added GitHub CI and release workflows for generic packages.

[cuichenli]

My only concern about getting parameters from the parameter store is that the users may need to find another tool/mechanism to store the parameters into the parameter store.

[apgrucza]

I tried using environment variables for parameters but they're not supported for Lambda@Edge.

Most users would already be using a tool such as Terraform or CloudFormation to deploy their CloudFront distribution and Lambda function. But if they are manually deploying these then yes, they will also have to manually deploy the parameters/secrets.

I think generally users would want the parameters/secrets to be owned by Terraform or CloudFront so that their lifecycle is managed automatically, e.g. deleted when the CloudFront distribution is deleted. It also lets them set attributes such as tags and rotation rules in a consistent manner.