More minor updates to README.md.

Minor update to README.md.

This commit includes a major revision to the project.

Updated the instructions for the createstack build command.

This commit finalizes a number of important changes:

Fixed a bug where the scripts would fetch Sales and Marketing datasets from a public AWS S3 bucket instead of the bucket to which files arre uploaded as part of the ETL flow.

Added another parameter, SourceDataBucketName.

Initial commit of Athena Runner.

Initial commit.

Reset sfn_activity_arn to <NO-DEFAULT>.

Fixed typo.

Removed dependency on managed IAM policy. Replaced by embedded policy.

Fixed typo in README.

Initial commit.