Enforce consistent JavaScript style

Describe request or inquiry

• Let's use a linter such as ESLint to enforce consistent code style in the JavaScript/Node.js microservices.
• Ideally, consistent code style would be enforced automatically (e.g., via Google Cloud Build) during pull-request creation.
• We could use eslint-config-google.

What purpose/environment will this feature serve?

• Consistent code style improves readability.
• Adding automation will allow contributors of this repository to focus on more important concerns.