API Gateway Authorizer

[nzoschke]

We can lift the JWTClaims helper out of our handler functions and into an API Gateway Authorizer, further reducing application code and increasing security.

Support for this in SAM is questionable. It doesn't look like a Serverless::Function supports adding an authorizer yet, but maybe you can assign then via Swagger.

• https://github.com/awslabs/serverless-application-model/issues/248
• https://github.com/awslabs/serverless-application-model/issues/25
• https://github.com/awslabs/serverless-application-model/issues/49

[nzoschke]

Looks like support is coming soon: https://github.com/awslabs/serverless-application-model/pull/546