SAM Template for C++ S3 Lambda Example

After much searching I can't find an example of a C++ lambda function deployed with SAM.

I think the addition of a SAM example would be very useful for user starting to develop C++ Lambda functions.

Start by reviewing the repository for existing Lambda examples and any SAM-related setup. Add a SAM example for deploying a C++ Lambda function using S3, then verify that the example is complete and usable for someone starting a C++ Lambda project.

Written by the indexing model from the issue text.