Set up ESLint for dependency-discovery

[JerryHue]

Issue This PR Addresses

Fixes #3154

Type of Change

• Bugfix: Change which fixes an issue
• New Feature: Change which adds functionality
• Documentation Update: Change which improves documentation
• UI: Change which improves UI

Description

This PR sets up the eslint configuration for the dependency-discovery service. It also fixes current eslint issues that occurred when running the linter.

Steps to test the PR

1. Pull my changes
2. Checkout my branch (git checkout issue-3154)
3. Ensure you have the proper dependencies installed (pnpm install)
4. Run pnpm lint.

Checklist

• Quality: This PR builds and passes our npm test and works locally
• Tests: This PR includes thorough tests or an explanation of why it does not
• Screenshots: This PR includes screenshots or GIFs of the changes made or an explanation of why it does not (if applicable)
• Documentation: This PR includes updated/added documentation to user exposed functionality or configuration variables are added/changed or an explanation of why it does not(if applicable)

[gitpod-io]