Adding support for Systems Manager Parameter Store

Not 100% sure if you consider this under the scope of the project, but I think this would be extremely useful:
Adding support for Systems Manager Parameter Store (retrieving / setting params), so you could easily use more sensitive data, like API keys, credentials, etc., that you wouldn't want committed into your source code.
There is a nice implementation in this AWS blog post that could probably be integrated into Chalice:
https://aws.amazon.com/blogs/compute/sharing-secrets-with-aws-lambda-using-aws-systems-manager-parameter-store/

Start by reading the linked AWS blog post and reviewing Chalice's existing configuration and deployment entry points; the issue names no specific files or tests. Done should mean Chalice supports retrieving and setting Systems Manager Parameter Store values for sensitive data such as API keys and credentials.

Written by the indexing model from the issue text.