Updating site to use USWDS styles (#509)

* Updated header and footer
* Updated fonts
* Moved files around and updated gulpfile to correct the build process when it goes to production
* Adjusted grid templating
* Added images to assets
* Update app/templates/components/uk_components/footer/template.njk

Co-authored-by: Steven Reilly <stvnrlly@users.noreply.github.com>

app/templates/views/notifications/notification.html

@@ -20,7 +20,7 @@
     {{ page_header(
       1|message_count_label(template.template_type, suffix='') | capitalize
     ) }}
-    <p class="govuk-body">
+    <p>
       {% if help %}
         ‘{{ template.name }}’
       {% else %}
@@ -51,7 +51,7 @@
     {% endif %}
 
     {% if current_user.has_permissions('send_messages') and current_user.has_permissions('view_activity') and template.template_type == 'sms' and can_receive_inbound %}
-      <p class="govuk-body">
+      <p>
         <a class="govuk-link govuk-link--no-visited-state" href="{{ url_for('.conversation', service_id=current_service.id, notification_id=notification_id, _anchor='n{}'.format(notification_id)) }}">See all text messages sent to this phone number</a>
       </p>
     {% endif %}