Refactor html templates

This commit entirely refactors the use of html templates. Instead of
inheriting from a shared template, we insert the results into a base
template.

internal/dis/component/auth/panel/templates/user.html

@@ -1,7 +1,3 @@
-{{ template "_base.html" . }}
-{{ define "title" }}{{ .User.User }}{{ end }}
-
-{{ define "content" }}
 <div class="pure-u-1">
     <p>
         <ul>
@@ -79,6 +75,4 @@
             </table>
         </div>
     </div>
-</div>
-
-{{ end }}
+</div>