Upgrade to Node.js LTS

[jwoo92]

Description WIP

This project needs upgraded to the current LTS version of Node.js.

Upgrading to v16 LTS is straight forward. After upgrading, all that is needed is to smoke test the request flows and observe expected behavior without any regressions.

TODO:

• Upgrade .nvmrc to v16
• Update package files to reflect v16
• Smoke test API flows