Strip/update dependencies

Unused/missing dependencies identified via:

```
npm install -g depcheck && depcheck
```

Updated remaining dependencies via:

```
npm install -g npm-check-updates && npm-check-updates -u
```

Applied changes via:
```
rm -rf node_modules
npm install
npm run format
npm run build
```

The prettier config was loaded in eslint, but no rule applied. depcheck thus reported eslint-plugin-prettier as unused. By not loading the prettier eslint config also eslint-config-prettier could be removed.

Less dependencies = lees breakages / vulnerabilities / updates.

.eslintrc.js

@@ -6,8 +6,7 @@ module.exports = {
   },
   root: true,
   extends: [
-    "eslint:recommended",
-    "prettier"
+    "eslint:recommended"
   ],
   parser: "@typescript-eslint/parser",
   parserOptions: {