GUI: migrate storage from PostgreSQL to SQLite and expose conf download

gui/templates/peer_created.html

@@ -2,6 +2,7 @@
 {% block content %}
 <h2>Peer создан: {{ name }}</h2>
 <p>PublicKey: <span class="mono">{{ public_key }}</span></p>
+<p><a href="data:text/plain;charset=utf-8,{{ client_conf | urlencode }}" download="{{ name }}.conf">Скачать {{ name }}.conf</a></p>
 <div class="grid2">
   <div>
     <h3>QR</h3>