Convert english translation file

- convert english translation to translate key
- remove baggy template for login (never used since user isn't logged in and it'll use the default theme: material)
- fix tests about text in response (now checking translation key instead of translated text)
- remove all ugly `<div class="hidden">{{ form_rest(form) }}</div>`

src/Wallabag/UserBundle/Resources/views/layout.html.twig

@@ -0,0 +1,23 @@
+{% extends "WallabagCoreBundle::layout.html.twig" %}
+
+{% block title %}{{ 'security.login.page_title'|trans }}{% endblock %}
+
+{% block body_class %}login{% endblock %}
+
+{% block menu %}{% endblock %}
+{% block messages %}{% endblock %}
+
+{% block content %}
+<main class="valign-wrapper">
+    <div class="valign row">
+        <div class="card sw">
+            <div class="center"><img src="{{ asset('bundles/wallabagcore/themes/material/img/logo-other_themes.png') }}" alt="wallabag logo" /></div>
+            {% block fos_user_content %}
+            {% endblock fos_user_content %}
+        </div>
+    </div>
+</main>
+{% endblock %}
+
+{% block footer %}
+{% endblock %}