add support for AWS Secrets Manager

[bruce-szalwinski-he]

Over in #1105, there is a request to add publish support for AWS Parameter Store. I second that and also need support for AWS Secrets Manager. I was studying how the publish mechanism works and prepared for additional destinations by fixing the destination logic, #1936. I've looked through the open issues and I see mention of a plugin framework, #1352, so that sops doesn't have to support all of these various encrypt / publish mechanisms, but I don't think that work has been completed. Would you be open for contributions that add support for Secrets Manager and/or Parameter Store?