launcher: option to close the terminal after a clean exit (#1869)

launcher: close the terminal after a clean exit and run several games at once

Co-authored-by: nmzik <Nmzik@mail.ru>

src/launcher/forms/main_dialog.ui

@@ -112,6 +112,13 @@
          </property>
         </widget>
        </item>
+       <item>
+        <widget class="QCheckBox" name="close_terminal">
+         <property name="text">
+          <string>Close terminal automatically</string>
+         </property>
+        </widget>
+       </item>
        <item>
         <layout class="QHBoxLayout" name="themeLayout">
          <item>