IO/UI should be relaxed to only trigger when the output is not in one package

[Luro02]

Summary

Currently it checks that everything is in a single class. This is too strict for projects with many packages and classes, where one may have an output in multiple command classes.

In early submissions where there is not a lot of code (everything in one package), we could keep the current behaviour.

TODO: When the project looks like this:

edu.kit.informatik
| Main
| model
  | ...
| ui
  | commands
    | QuitCommand
    | AddCommand
  | extras
    | SomeHelper
  | UserInterface

It should be okay to have all the IO in the ui package and it's "subpackages".

Lint Name

No response

Reproducer

<code>