feat: show previous versions of edited notes

[dakkar]

Summary

• an API endpoint, that works like /notes/show but returns all versions of the note
• a button or menu item on the web frontend, shown only for edited notes, that calls that endpoint and shows all the versions
  • probably in a "window" like "… / ⓘdetails" already does

[Mar0xy]

a button or menu item on the web

I would probably put the versions into the edited icon as a menu that shows up on the notes

[dakkar]

so would I, but didn't want to sound prescriptive 😅