Review and enhance metric support for payment service (node.js)

[cartersocha]

The following are requirements for metrics in the project. Not all services will meet all requirements.

• [ ] Service metrics should not be duplicative of trace-derived metrics.
• [ ] Services should emit multiple business metrics where appropriate.
• [ ] Services should emit trace exemplars for their metrics.
• [ ] Services should use push metrics where possible.
• [ ] Services should explicitly read baggage where needed.
• [ ] Collectors should perform metric transforms to normalize resource and service metrics.

Referencing issue: https://github.com/open-telemetry/opentelemetry-demo-webstore/issues/43