QML imports are currently not all consistent. We need to agree on which names the imports will have, which order and which versions.
Then we should apply them to as many places as possible.
I think think we should use this example as a base (versions can of course be different, only use needed imports):
```
import QtQuick 2.5
import QtQuick.Layouts 1.0
import QtQuick.Controls 2.5 as QQC2
import QtQuick.Dialogs 1.1 as QtDialogs
import org.kde.kirigami 2.5 as Kirigami
import org.kde.plasma.core 2.0 as PlasmaCore
import org.kde.plasma.components 2.0 as PlasmaComponents2
import org.kde.plasma.extras 2.0 as PlasmaExtras
```