networks: Fix showing password during PPPoE edit

- Javascript was missing for the template altogether.  Added one similar
  to create case.

- Minor refactoring to existing javascript.

- Consistent styling for display label and field id.

plinth/modules/networks/forms.py

@@ -89,8 +89,8 @@ available over this interfaces. Select Internal only for trusted networks.'),
     username = forms.CharField(label=_('Username'))
     password = forms.CharField(label=_('Password'),
                                widget=forms.PasswordInput())
-    showpw = forms.BooleanField(label=_('show password'),
-                                required=False)
+    show_password = forms.BooleanField(label=_('Show password'),
+                                       required=False)
 
     def __init__(self, *args, **kwargs):
         """Initialize the form, populate interface choices."""

plinth/modules/networks/templates/connections_create.html

@@ -58,18 +58,15 @@
       }
     });
 
-    $('#id_showpw').change(function() {
-        //changing type attribute from password to text is prevented by
-        //most browsers make a new form field works for me
-        if ($('#id_showpw').prop('checked')) {
-          $('#id_password').replaceWith(
-            $('#id_password').clone().attr(
-            'type', 'text'));
-        } else {
-          $('#id_password').replaceWith(
-            $('#id_password').clone().attr(
-            'type', 'password'));
-        }
+    $('#id_show_password').change(function() {
+        // Changing type attribute from password to text is prevented by
+        // most browsers. Making a new form field works.
+        new_type = 'password';
+        if ($('#id_show_password').prop('checked'))
+            new_type = 'text';
+
+        $('#id_password').replaceWith(
+            $('#id_password').clone().attr('type', new_type));
       });
 
     })(jQuery);

plinth/modules/networks/templates/connections_edit.html

@@ -58,6 +58,17 @@
       }
     });
 
+    $('#id_show_password').change(function() {
+        // Changing type attribute from password to text is prevented by
+        // most browsers. Making a new form field works.
+        new_type = 'password';
+        if ($('#id_show_password').prop('checked'))
+            new_type = 'text';
+
+        $('#id_password').replaceWith(
+            $('#id_password').clone().attr('type', new_type));
+      });
+
     })(jQuery);
   </script>