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/service-settings/sms-sender/edit.html

@@ -20,7 +20,7 @@
   {{ page_header('Change text message sender') }}
   {% call form_wrapper() %}
     {% if inbound_number %}
-      <p class="govuk-body">
+      <p>
         <span class="bottom-gutter-1-3"> {{ sms_sender.sms_sender }} </span>
         <span class="hint"> This phone number receives replies and cannot be changed </span>
       </p>