Feature(pages): Add 404 page

To prevent loops, server errors will lead here instead of map page
This page can be static to prevent infinite loops
closes #9463

server/boot/z-lang-redirect.js

@@ -16,9 +16,9 @@ export default function redirectLang(app) {
 
     if (supportedLanguages[langCode]) {
       req.flash('errors', {
-        msg: `404: We couldn't find path ${ path }`
+        msg: `We couldn't find path ${ path }`
       });
-      return res.redirect('/map');
+      return res.render('404', { title: '404'});
     }
 
     // language aware redirect

server/views/404.jade

@@ -0,0 +1,20 @@
+extends ./layout
+
+block content
+    .spacer
+    .row
+        .col-sm-6.col-sm-offset-3
+            hr
+            .text-center
+                h1 404
+    .row
+        .col-sm-6.col-sm-offset-3
+            .text-center
+                h2 Ooops, we couldn't find that page.
+    .spacer
+    .row
+        .col-sm-6.col-sm-offset-3
+            .text-center
+                a.btn.signup-btn.btn-block(href='/map') Head to the Map
+            hr
+    .spacer