put shell in subdir, and add nix package

shell/widgets/MaterialButton.qml

@@ -0,0 +1,24 @@
+import QtQuick
+import ".."
+
+MouseArea {
+    id: root
+    hoverEnabled: true
+
+    property real radius: width / 2
+    property bool checked: false
+    property var activeColor: ShellSettings.colors["primary"]
+    property var inactiveColor: "transparent"
+
+    Rectangle {
+        color: root.containsMouse || root.checked ? root.activeColor : root.inactiveColor 
+        radius: root.radius
+        anchors.fill: parent
+
+        Behavior on color {
+            ColorAnimation {
+                duration: 200
+            }
+        }
+    }
+}