serverless-dynamodb-local examples need updating

[domdomegg]

The examples involving serverless-dynamodb-local are quite out of date. They use an older configuration API which makes it hard for new users to get started. In addition, the package serverless-dynamodb-local no longer works as the hardcoded URL it contains has broken, and it uses an old access key format that isn't compatible with new versions of DynamoDB Local.

We should update the docs to use the newer APIs, and probably the fixed packages.

Also see:

• https://github.com/99x/dynamodb-localhost/pull/78
• https://github.com/99x/serverless-dynamodb-local/pull/298
• https://github.com/raisenational/serverless-dynamodb/issues/33
• https://stackoverflow.com/a/76608752/5352227