feat: Customize Monaco's settings

Feature request: Add a locally saved JSON that will be appended to Monaco's settings, i.e.
```js
const editor = monaco.editor.create(container, { ...hardcodedSettings, ...JSON.parse(localStorage.monacoSettings) });
```

Specifically I want to set `{ "rulers": [100] }`, and instead of adding a toggle specifically for it I thought being more customizable would be better.