Set max width on error page and include Last login on error page

- Updated error_base template so that it contained the Root Vue component, which was the reason that the last login was not previously displaying
- Deleted unused css
- Created css variable max-page-width for use on the error page, topbar, and other full width elements

styles/components/_topbar.scss

@@ -12,7 +12,7 @@
     flex-direction: row;
     align-items: stretch;
     justify-content: space-between;
-    max-width: 1190px;
+    max-width: $max-page-width;
 
     a {
       color: $color-white;