[BaseVCS] Add splitter in submit editor.

Splitter between 'description' section and 'files' section. This makes it easier
to work with smaller screens.

Change-Id: Ie1d8c7a671faba270e6906504b3af56ff8c85e28
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>

src/libs/utils/submiteditorwidget.ui

@@ -15,6 +15,13 @@
   </property>
   <layout class="QVBoxLayout">
    <item>
+    <widget class="QSplitter" name="splitter">
+     <property name="orientation">
+      <enum>Qt::Vertical</enum>
+     </property>
+     <property name="childrenCollapsible">
+      <bool>false</bool>
+     </property>
      <widget class="QGroupBox" name="descriptionBox">
       <property name="title">
        <string>Descriptio&amp;n</string>
@@ -32,7 +39,11 @@
        </item>
       </layout>
      </widget>
-   </item>
+     <widget class="QWidget" name="verticalLayoutWidget">
+      <layout class="QVBoxLayout" name="verticalLayout_3">
+       <property name="topMargin">
+        <number>0</number>
+       </property>
        <item>
         <widget class="QGroupBox" name="groupBox">
          <property name="title">
@@ -60,6 +71,9 @@
        </item>
        <item>
         <layout class="QHBoxLayout" name="buttonLayout">
+         <property name="leftMargin">
+          <number>0</number>
+         </property>
          <item>
           <spacer name="horizontalSpacer">
            <property name="orientation">
@@ -77,6 +91,10 @@
        </item>
       </layout>
      </widget>
+    </widget>
+   </item>
+  </layout>
+ </widget>
  <customwidgets>
   <customwidget>
    <class>Utils::CompletingTextEdit</class>