feat: 404 Page (#22)

Author: esacteksab

layouts/404.html

@@ -0,0 +1,5 @@
+{{ define "main" }}
+  <h2>{{ ":question: HTTP 404 Page not found :question:" | .RenderString }}</h2>
+  <p>{{ "The page you requested cannot be found. Don't know what you're looking for but it's not here." | .RenderString }}</p>
+  <p><a href="{{ .Site.Home.RelPermalink }}">Return to the home page.</a></p>
+{{ end }}