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.

Commons/Settings.qml

@@ -146,6 +146,12 @@ Singleton {
       property real marginVertical: 0.25
       property real marginHorizontal: 0.25
 
+      // Bar outer corners (inverted/concave corners at bar edges when not floating)
+      property bool outerCorners: true
+
+      // Reserves space with compositor
+      property bool exclusive: true
+
       // Widget configuration for modular bar system
       property JsonObject widgets
       widgets: JsonObject {
@@ -182,6 +188,7 @@ Singleton {
     // general
     property JsonObject general: JsonObject {
       property string avatarImage: ""
+      property bool dimDesktop: true
       property bool showScreenCorners: false
       property bool forceBlackScreenCorners: false
       property real scaleRatio: 1.0