Most stuff here was recently changed. Some of it was where I found a pattern in something that was likely copy-pasted from somewhere else, so I did a global search and replace on that.
Contributes to issue CURA-5784.
As discussed with LukeChen-Ultimaker, we only want to display a button when there is really something up with the current set-up, not when there might be something up. Most users will be confused to see a button that always says that everything is fine.
This also simplifies the signal handling a lot.
Contributes to issue CURA-4557.
