Working user and link list, (big)restructure

This is now a workspace consisting of:
  * the pslink app (a wasm frontend for the admin interface)
  * the pslink binary
  * shared - modules for communication between the two above.

pslink/templates/not_found.html

@@ -0,0 +1,8 @@
+{% extends "base.html" %}
+
+{% block content %}
+<div class="center">
+    <h3>{{ fluent(key="not-found", lang=language) }}</h3>
+    <h2>&nbsp;</h2>
+</div>
+{% endblock %}