Preferences: Add checkbutton for use_keyring

gajim/data/gui/preferences_window.ui

@@ -2702,6 +2702,23 @@ to discover one from the server. (Example: stun.iptel.org)</property>
                         <property name="position">1</property>
                       </packing>
                     </child>
+                    <child>
+                      <object class="GtkCheckButton" id="use_keyring_checkbutton">
+                        <property name="label" translatable="yes">Use your system’s _keyring to store passwords</property>
+                        <property name="visible">True</property>
+                        <property name="can_focus">True</property>
+                        <property name="receives_default">False</property>
+                        <property name="halign">start</property>
+                        <property name="use_underline">True</property>
+                        <property name="draw_indicator">True</property>
+                        <signal name="toggled" handler="_on_use_keyring_toggled" swapped="no"/>
+                      </object>
+                      <packing>
+                        <property name="expand">False</property>
+                        <property name="fill">True</property>
+                        <property name="position">2</property>
+                      </packing>
+                    </child>
                     <child>
                       <object class="GtkBox">
                         <property name="visible">True</property>
@@ -2751,7 +2768,7 @@ to discover one from the server. (Example: stun.iptel.org)</property>
                       <packing>
                         <property name="expand">False</property>
                         <property name="fill">True</property>
-                        <property name="position">2</property>
+                        <property name="position">3</property>
                       </packing>
                     </child>
                     <child>
@@ -2768,7 +2785,7 @@ to discover one from the server. (Example: stun.iptel.org)</property>
                       <packing>
                         <property name="expand">False</property>
                         <property name="fill">True</property>
-                        <property name="position">3</property>
+                        <property name="position">4</property>
                       </packing>
                     </child>
                   </object>

gajim/gtk/preferences.py

@@ -423,6 +423,9 @@ def create_av_combobox(opt_name, device_dict, config_name=None,
         st = app.config.get('log_contact_status_changes')
         self._ui.log_show_changes_checkbutton.set_active(st)
 
+        st = app.config.get('use_keyring')
+        self._ui.use_keyring_checkbutton.set_active(st)
+
         self._ui.enable_logging.set_active(app.get_debug_mode())
         self._ui.enable_logging.show()
 
@@ -1052,6 +1055,10 @@ def update_proxy_list(self):
     def on_log_show_changes_checkbutton_toggled(self, widget):
         self.on_checkbutton_toggled(widget, 'log_contact_status_changes')
 
+    # Use system’s keyring
+    def _on_use_keyring_toggled(self, widget):
+        self.on_checkbutton_toggled(widget, 'use_keyring')
+
     # Enable debug logging
     def on_enable_logging_toggled(self, widget):
         app.set_debug_mode(widget.get_active())