[Qt] rename In:/Out: to Received/Sent in traffic tab

- collides with In:/Out: used for displaying number of
  connections when translating

src/qt/forms/rpcconsole.ui

@@ -559,7 +559,7 @@
               <item>
                <widget class="QLabel" name="label_16">
                 <property name="text">
-                 <string>In:</string>
+                 <string>Received</string>
                 </property>
                </widget>
               </item>
@@ -639,7 +639,7 @@
               <item>
                <widget class="QLabel" name="label_17">
                 <property name="text">
-                 <string>Out:</string>
+                 <string>Sent</string>
                 </property>
                </widget>
               </item>