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/views/platform-admin/_base_template.html

@@ -9,8 +9,8 @@
       </div>
       <a href="{{ url_for('main.choose_account') }}" class="govuk-link govuk-link--no-visited-state navigation-service-switch">Switch service</a>
     </div>
-    <div class="govuk-grid-row">
-      <div class="govuk-grid-column-one-quarter">
+    <div class="grid-row">
+      <div class="tablet:grid-col-2">
         <nav class="navigation">
             {% for link_text, url in [
             ('Summary', url_for('main.platform_admin')),
@@ -34,7 +34,7 @@
           {% endfor %}
         </nav>
       </div>
-      <div class="govuk-grid-column-three-quarters">
+      <div class="grid-col-10 tablet:grid-col-10">
       {% block backLink %}{% endblock %}
         <main class="govuk-main-wrapper column-main govuk-!-padding-top-0 govuk-!-padding-bottom-0" id="main-content" role="main">
           {% block content %}