Gui: Delete duplicate file in library.

Delete duplicate file StackViewNavController.ui in Gui/library
which already exists in Gui/library/ui. Update CMakeLists.txt

src/CMakeLists.txt

@@ -299,7 +299,6 @@ ELSE(NOT WITH_GUI)
         Gui/export/ShareOnInternet.ui
         Gui/import/ui/ImportController.ui
         Gui/import/ui/TagWidget.ui
-        Gui/library/StackViewNavController.ui
         Gui/library/ui/MediaCellView.ui
         Gui/library/ui/MediaLibrary.ui
         Gui/library/ui/StackViewNavController.ui

src/Gui/library/StackViewNavController.ui

-<?xml version="1.0" encoding="UTF-8"?>
-<ui version="4.0">
- <class>StackViewNavController</class>
- <widget class="QWidget" name="StackViewNavController">
-  <property name="geometry">
-   <rect>
-    <x>0</x>
-    <y>0</y>
-    <width>400</width>
-    <height>46</height>
-   </rect>
-  </property>
-  <property name="windowTitle">
-   <string>Form</string>
-  </property>
-  <layout class="QHBoxLayout" name="horizontalLayout">
-   <item>
-    <widget class="QPushButton" name="previousButton">
-     <property name="text">
-      <string>Previous</string>
-     </property>
-    </widget>
-   </item>
-   <item>
-    <widget class="QLabel" name="title">
-     <property name="sizePolicy">
-      <sizepolicy hsizetype="Expanding" vsizetype="Preferred">
-       <horstretch>0</horstretch>
-       <verstretch>0</verstretch>
-      </sizepolicy>
-     </property>
-     <property name="text">
-      <string>TextLabel</string>
-     </property>
-     <property name="alignment">
-      <set>Qt::AlignCenter</set>
-     </property>
-    </widget>
-   </item>
-  </layout>
- </widget>
- <resources/>
- <connections/>
-</ui>