[IMP] website: Limit size of favicon

Before this commit, if you uploaded a big image, it would break the settings
screen.

Now, the image will have its displayed size limited to 90px

addons/website/views/res_config_settings_views.xml

@@ -26,7 +26,7 @@
                                             </div>
                                             <div class="row">
                                                 <label class="col-md-3 o_light_label" for="favicon" />
-                                                <field name="favicon" widget="image"/>
+                                                <field name="favicon" widget="image" class="pull-left oe_avatar"/>
                                             </div>
                                         </div>
                                     </div>