New windowing system

Large commit that totally refactor of the way we handle the bar and
panels.

Testing should focus on Panels, Bar, Keyboard Focus, IPC calls.

Changes brief:
- One NFullScreenWindow per screen which handle it's bar and dedicated
panels.
- Added shadows
- Reintroduced dimming
- New panels animations
- Proper Z ordering
- Panels on overlay laywer is not reimplemented, if we do it then the
bar will be on the Overlay too
- Panel dragging was not reimplemented, to be discussed before
reimplementing
- Still a WIP, need to work more on shadows and polishing + debugging.

Modules/ControlCenter/Cards/ProfileCard.qml

@@ -60,8 +60,9 @@ NBox {
         icon: "settings"
         tooltipText: I18n.tr("tooltips.open-settings")
         onClicked: {
-          settingsPanel.requestedTab = SettingsPanel.Tab.General
-          settingsPanel.open()
+          var panel = PanelService.getPanel("settingsPanel", screen)
+          panel.requestedTab = SettingsPanel.Tab.General
+          panel.open()
         }
       }
 
@@ -69,8 +70,8 @@ NBox {
         icon: "power"
         tooltipText: I18n.tr("tooltips.session-menu")
         onClicked: {
-          sessionMenuPanel.open()
-          controlCenterPanel.close()
+          PanelService.getPanel("sessionMenuPanel", screen)?.open()
+          PanelService.getPanel("controlCenterPanel", screen)?.close()
         }
       }
 
@@ -78,7 +79,7 @@ NBox {
         icon: "close"
         tooltipText: I18n.tr("tooltips.close")
         onClicked: {
-          controlCenterPanel.close()
+          PanelService.getPanel("controlCenterPanel", screen)?.close()
         }
       }
     }