Add a full working Serverless API example using APIGateway, Lambda, DynamoDB

[Andrea-Scuderi]

Add an Example to show how to build a Serverless REST API using:

• APIGateway
• Lambda
• DynamoDB

Motivation:

To encourage the adoption of the library I suggest to add a working example with a common use case in the AWS world.

The discussion started https://forums.swift.org/t/examples-and-getting-started-guides/37829 haven't produced a decision.

Modifications:

• Add a new target ProductAPI to LambdaFunctions examples
• Add SAM and Serverless templates to deploy the new example
• Add ProductAPI sources using on the Soto library

Result:

• Provide a full working example with a full Serverless API with a database

[swift-server-bot]

Can one of the admins verify this patch?

[swift-server-bot]

Can one of the admins verify this patch?

[swift-server-bot]

Can one of the admins verify this patch?

[swift-server-bot]

Can one of the admins verify this patch?

[tomerd]

closing in inactive PRs, feel free to re-open if still relevant