Update to FOSUserBundle 3.1

Also remove some deprecation from Symfony.
Use `LegacyEventDispatcherProxy` to handle Symfony 4 dispatch from FOSUser

templates/bundles/FOSUserBundle/ChangePassword/changePassword_content.html.twig

@@ -0,0 +1,12 @@
+{% trans_default_domain 'FOSUserBundle' %}
+
+{{ form_start(form, {'action': path('fos_user_change_password'), 'attr': {'class': 'fos_user_change_password'}}) }}
+    <div class="card-content">
+        <div class="row">
+            {{ form_widget(form) }}
+            <div>
+                <input type="submit" value="{{ 'change_password.submit'|trans }}" />
+            </div>
+        </div>
+    </div>
+</form>