Support additional track tool bar

Author: CrSjimo

src/plugins/visualeditor/qml/PianoRollView.qml

@@ -432,9 +432,10 @@ Item {
                                             color: Theme.foregroundPrimaryColor
                                             font: Theme.font
                                         }
-                                        Item {
+                                        StackLayout {
                                             Layout.fillWidth: true
                                             Layout.fillHeight: true
+                                            data: [layout.item?.toolBar ?? null]
                                         }
                                         ToolButton {
                                             implicitWidth: 20

src/plugins/visualeditor/qml/additionaltracks/ParameterTrack.qml

@@ -23,6 +23,10 @@ QtObject {
     readonly property Component parameterTrackComponent: Item {
         id: control
         required property QtObject contextObject
+        readonly property Item toolBar: Rectangle {
+            // TODO
+            color: "red"
+        }
         implicitHeight: 40
         Layout.fillWidth: true
         Layout.fillHeight: true