Add support for enable/disable of accept/reject buttons

src/QmlControls/QGCPopupDialog.qml

@@ -18,6 +18,10 @@ Item {
     height: childrenRect.height
 
     signal hideDialog
+    signal enableAcceptButton
+    signal disableAcceptButton
+    signal enableRejectButton
+    signal disableRejectButton
 
     Keys.onReleased: {
         if (event.key === Qt.Key_Escape) {

src/QmlControls/QGCPopupDialogContainer.qml

@@ -156,9 +156,17 @@ Popup {
         }
     }
 
+    function disableAcceptButton() {
+        acceptButton.enabled = false
+    }
+
     Connections {
         target:                 dialogComponentLoader.item
         onHideDialog:           close()
+        onEnableAcceptButton:   acceptButton.enabled = true
+        onEnableRejectButton:   rejectButton.enabled = true
+        onDisableAcceptButton:  acceptButton.enabled = false
+        onDisableRejectButton:  rejectButton.enabled = false
     }
 
     Rectangle {