Remove unecessary id and class from product page

Stopped using `#content` on the product page - this was from GOV.UK elements.
Also removed the `override-elements-content` class since the page looks
the same without it.

app/assets/stylesheets/app.scss

@@ -187,10 +187,6 @@ details .arrow {
   margin-top: 5px;
 }
 
-#content.override-elements-content {
-  padding-bottom: 0;
-}
-
 .multiple-choice input:disabled+label {
   opacity: 1;
   color: $secondary-text-colour;

app/templates/views/signedout.html

@@ -12,7 +12,7 @@
 {% block content %}
 
   <div class="product-page-intro">
-    <div class="product-page-intro-wrapper override-elements-content" id="content">
+    <div class="product-page-intro-wrapper">
       <nav class="breadcrumbs breadcrumbs--inverse" aria-label="Breadcrumbs">
        <ol itemscope itemtype="http://schema.org/BreadcrumbList">
          <li class="breadcrumbs__item" itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem">