Best way to pass jwt credentials and query args to schema

Hello, thank you for your really nice job! I am using your framework and enjoying a lot.

I would like to ask you if it is possible to pass jwt credentials and query args to the schema defined in arguments. For example, I have:

```python
@bp.route('/users/')
class UserById(MethodView):
@jwt_required
@bp.arguments(UserEditSchema)
@bp.response(UserEditSchema)
def put(self, args, id):
username = get_jwt_identity()
logged_user = User.get_by_username(username)
user = User.query.get(id)
```

The thing is that I want to check if user == logged_user inside UserEditSchema

Thank you!

Start at the UserById.put entry point and compare how @jwt_required and @bp.arguments pass context to UserEditSchema. Determine whether JWT identity and the route/query values should be available during schema handling, then define focused coverage and document the supported usage or limitation.

Written by the indexing model from the issue text.