This widget can't set its width to the width of its children, since its children anchor to its right-hand side which depends on the width.
This fixes the following warning in the log:
2020-03-20 14:25:20,351 - WARNING - [MainThread] UM.Qt.QtApplication.__onQmlWarning [406]: file:///home/trin/Gedeeld/Projects/Cura/plugins/PrepareStage/PrepareMain.qml:16:5: QML ActionPanelWidget: Binding loop detected for property width
Done during Turbo Testing and Tooling.
This way it's more dynamic: You don't need to hardcode the plug-in name in the widget to see whether or not it's visible.
Contributes to issue CURA-6086.
They can then decide if it needs to be there. For instance, the monitor stage doesn't want to have this panel. Also each stage can position it where they like, and in the near future I'll make a feature to let it decide whether or not to show the preview button.
Contributes to issue CURA-6086.
The settings panel can now be so long that they overlap (if the user so chooses). This causes the action panel to be hidden behind the settings. We'd prefer to show the action panel in front, always.
Contributes to issue CURA-6054.
