(Misc) Ensure consistent response format

## Issue Details
Every response of the API should have a specific format so the client should always expect the same structure from their side.

### Workaround
That said, for every `return` statement inside the `routes.py` is good to have the following response:

```python
return jsonify({
    "title": "some-title",
    "msg": "some-message",
}), 200 # or other code
```