Add SigV4 support

[trevorbonas]

Changes:

• Connector:

  • enable_sigv4_auth environment variable has been added. If this environment variable is true, basic auth headers will be ignored and the connector will attempt to use local credentials.

• SAM template:

  • EnableSigV4Auth parameter has been added, which sets authentication to AWS_IAM for the routes (/write and /read) and passes in the enable_sigv4_auth environment variable to the connector Lambda function with the value true.
  • Events have been removed from the Lambda function and replaced with routes to configure SigV4 authentication.
  • The APIGateway resource has been changed to an AWS::ApiGatewayV2::Api with protocol set to HTTP. This was done because using API Gateway resources (such as AWS::ApiGatewayV2::Route resources) on an AWS::Serverless::HttpApi resource has undefined behaviour.

• Documentation:

  • Launch (SigV4) links have been added to the DEVELOPER_README, which set the EnableSigV4Auth parameter to true.

• Integration tests passed (go test -v ./integration/).

• Unit tests passed (go test -tags=unit -cover -v ./timestream ./).

• TLS tests passed (go test -v ./integration/tls).

• Correctness tests passed (go test -v ./correctness).

• Stack deployment tested with SigV4 enabled using the OpenTelemetry collector.

• Stack deployment tested with SigV4 disabled using Prometheus for reading and writing.

[forestmvey]

Looks good!