Refine mobileform settings

Numerous refinements to the new mobileform setting pages 
- Ensure left and right padding at the top level is 0 for mobile
- Centre align the avatar in the account editor page and add tooltip to button
- Fix the bubble/compact mode setting so that it fits when thin, i.e on mobile
- Fix the loading placeholder in device settings

src/qml/Settings/GlobalNotificationsPage.qml

@@ -12,6 +12,8 @@ import org.kde.neochat 1.0
 
 Kirigami.ScrollablePage {
     title: i18nc("@title:window", "Notifications")
+    leftPadding: 0
+    rightPadding: 0
     ColumnLayout {
         id: notificationLayout