Update dashboard and template flow (#514)

* Updated header and footer
* Moved files around and updated gulpfile to correct the build process when it goes to production
* Updated fonts
* Adjusted grid templating
* Adding images to assets
* Updated account pages, dashboard, and pages in message sending flow
* Updated the styling for the landing pages in the account section once logged in

app/templates/components/show-more.html

@@ -1,6 +1,6 @@
 {% macro show_more(url, label, with_border=True) %}
   <a
     href="{{ url }}"
-    class="govuk-link govuk-link--no-visited-state show-more{% if not with_border %}-no-border{% endif %}"
+    class="usa-link show-more{% if not with_border %}-no-border{% endif %}"
   ><span>{{ label }}</span></a>
 {% endmacro %}