Let the wizard automatically create a cloudfront distribution for static s3 sites

[ubergeek42]

Let the wizard help users configure a CloudFront distribution that serves their S3 static site. Should make it much simpler for people to get started with if that's all they use.

[fregante]

This feature probably belong to its own tool rather than lambda-letsencrypt. As the name suggest this should probably just handle the certificates.