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/ImportBundle/Import/PocketImport.php

@@ -60,7 +60,7 @@ class PocketImport implements ImportInterface
      */
     public function getDescription()
     {
-        return 'This importer will import all your Pocket data. Pocket doesn\'t allow us to retrieve content from their service, so the readable content of each article will be re-fetched by wallabag.';
+        return 'import.pocket.description';
     }
 
     /**
@@ -139,7 +139,7 @@ class PocketImport implements ImportInterface
     /**
      * Get whether articles must be all marked as read.
      */
-    public function getRead()
+    public function getMarkAsRead()
     {
         return $this->markAsRead;
     }

src/Wallabag/ImportBundle/Import/WallabagV1Import.php

@@ -67,7 +67,7 @@ class WallabagV1Import implements ImportInterface
      */
     public function getDescription()
     {
-        return 'This importer will import all your wallabag v1 articles. On your config page, click on "JSON export" in the "Export your wallabag data" section. You will have a "wallabag-export-1-xxxx-xx-xx.json" file.';
+        return 'import.wallabag_v1.description';
     }
 
     /**

src/Wallabag/ImportBundle/Import/WallabagV2Import.php

@@ -27,7 +27,7 @@ class WallabagV2Import extends WallabagV1Import implements ImportInterface
      */
     public function getDescription()
     {
-        return 'This importer will import all your wallabag v2 articles. Go to All articles, then, on the export sidebar, click on "JSON". You will have a "All articles.json" file.';
+        return 'import.wallabag_v2.description';
     }
 
     /**