feat(boto3): Add Step Functions service extension

[pabloDeputter]

• Add following span attributes:
  • The ARN of the AWS Step Functions Activity (https://getsentry.github.io/sentry-conventions/attributes/aws/#aws-step_functions-activity-arn): aws.step_functions.activity.arn
  • The ARN of the AWS Step Functions State Machine (https://getsentry.github.io/sentry-conventions/attributes/aws/#aws-step_functions-state_machine-arn): aws.step_functions.state_machine.arn
  • Primary identifier for an individual workflow execution (not yet added in OTel semconv. or sentry-semconv.): aws.step_functions.execution.arn
    • Make separate issue!

[linear-code]

PY-2778