QA/Lint: Prettier + ESLint for the webapp

[GODrums]

Description

Summary

Adds Prettier + ESLint to the webapp. Configs are similar to the ones used in the Artemis-Repo. Triggers are set to:

• Github Action
  • On Pull Request in /webapp
  • On Push in the develop-branch with changes in /webapp
• Commands
  • ESLint: npm run lint and npm run lint:fix
  • Prettier: npm run prettier:check and npm run prettier:write

This PR does NOT include Prettier formatting / ESL linting fixes yet, only the initial setup to avoid potential merge conflicts.

Motivation

The project should follow consistent code conventions and standards. Prettier and ESLint are the most common combination in attaining such goals.

Key Changes

• Simple / Loose Prettier config similar to .editorconfig
• ESLint config taken from the Artemis-repo with small adjustments for our tech stack
• Github workflow for automatic execution of both commands for pull requests (untested for now)

Checklist

• [x] Review Prettier config options
• [x] Review ESLint rules
• [x] Execute workflow at least once for testing

TODOs / Next up

• Fix existing Prettier formatting errors
• Fix existing ESLint errors
• Add commands to Readme / Contributing Guidelines

General

• [x] PR title is clear and descriptive
• [x] PR description explains the purpose and changes
• [ ] Code follows project coding standards
• [x] Self-review of the code has been done
• [x] Changes have been tested locally
• [x] Screenshots have been attached (if applicable)
• [ ] Documentation has been updated (if applicable)