Add VSCode eslint setup to documentation

[kevinmamaqi]

{
  "editor.formatOnSave": true,
  "[json]": {
    "editor.formatOnSave": true,
    "editor.defaultFormatter": "esbenp.prettier-vscode"
  },
  "[javascript]": {
    "editor.formatOnSave": true,
    "editor.defaultFormatter": "dbaeumer.vscode-eslint"
  },
  "eslint.workingDirectories": [
    "frontend",
    "backend",
    "e2e"
  ],
  "javascript.format.insertSpaceAfterOpeningAndBeforeClosingNonemptyBraces": false
}