Quick edit

feat: add a quick edit workflow using the up arrow key

neochat now supports a quick edit shortcut, which helps to edit the last message from the user in a room.

PS: This is not to be confused with !207 (merged) . This is not related with that Quick edit 😄

PPS: I am not sure if it has a lot of redundant code which could be optimized. Please advise me, I am a beginner in C++/QML 😅