Refactor: eliminate old infoview implementations

[joneugster]

Current state:

• editor mode: has a plain infoview included for testing
• typewriter: layout but no editor and no functionality
• old implementation is under src/infoview, new one should go into src/components/infoview

Todos:

• Add the single-line editor inside the typewrite back
• Recover basic functionality to write a proof step (single line) and add it to the main editor
• Recover display of previous proof steps
• Recover other features, such as chat scrolling, ...
• Implement an infoview for editor mode using the display we have in the typewriter mode.
• ...?
• finally: remove the folder src/infoview with the old implementation