DynamoDB storage for orders + Kinesis streams for orders & products service

[daemon-joe]

Issue #, if available: N/A

Description of changes: This PR contains four additions to the project to support integration with the AWS Customer 360 Data Hub project. These changes are as follows:

• Replace in-memory DB for orders service with Dynamo DB table
• Allow input of a Kinesis stream ARN for the products and orders service
• Add service load balancer URLs as outputs of the top-level template
• Added --private flag to the staging script to expose functionality previously only accessible by direct modification fo the script. Default behaviour remains the same.

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