add prettier for auto formatting (#231)

* [Prettier] Add "prettier"

Makes the formatting of the code consistent.
By using the eslint-plugin-prettier formatting issues will be highlighted as a lint error.
These errors will be auto fixed by running "lint --fix" (which can be done automatically on file save)

* [Prettier] Add "prettier" - Fix formatting

package.json

@@ -58,11 +58,14 @@
     "eslint": "^7.2.0",
     "eslint-config-airbnb": "18.2.1",
     "eslint-config-airbnb-typescript": "^14.0.0",
+    "eslint-config-prettier": "^8.6.0",
     "eslint-plugin-import": "^2.22.1",
     "eslint-plugin-jsx-a11y": "^6.4.1",
     "eslint-plugin-no-relative-import-paths": "^1.5.2",
+    "eslint-plugin-prettier": "^4.2.1",
     "eslint-plugin-react": "^7.21.5",
     "eslint-plugin-react-hooks": "^1.7.0",
+    "prettier": "^2.8.2",
     "typescript": "^4.8.4"
   }
 }