AWS Lambda VPC config is an optional configuration and which needs to both subnet_ids and
security_group_ids to tie the lambda function to a VPC. We should make it optional if
both subnet_ids and security_group_ids are not net which would add better flexiblity in
creation of more useful modules as there are "if else" checks. Without this we are creating
duplicate modules one with VPC and one without VPC resulting in various anomalies.
Previously we linked to the whole request body definition for valid values of `runtime`.
Now we link directly to the docs for `Runtime`, which will hopefully make it easier to find the valid values.
This fixes#4570.
Paul Stack