Add option to setup in VPC

[timogoosen]

I think many people who will be using this will be worried about PCI compliance.

Re this doc: https://aws-quickstart.github.io/quickstart-compliance-pci-fsbp-remediation/

[PCI.Lambda.1] AWS Lambda functions should prohibit public access.

[PCI.Lambda.2] AWS Lambda functions should be in a VPC.

I think many people would find it super helpful if you add an option to set the Lambda up in a VPC.