List all S3 buckets from an AWS Lambda function using aws-sdk

AWS is not awesome because of Lambda, S3, DynamoDB, IAM and other services.

It's awesome because you get to combine them together in order to solve your problems.

In this lesson we're going to learn how to use IAM roles and policies effectively in order to allow an AWS Lambda function to list all S3 buckets using the aws-sdk listBuckets method.

We're also going to learn what's the principle of least privilege in AWS