clean babillard, remove option for multiple boards

src/babillard_page.eml.html

@@ -1,17 +1,13 @@
-let f ~board request =
-%let board = Format.asprintf "%a" Babillard.pp_board board in
+let f request =
 <script type="text/javascript" src="/assets/js/js_babillard.js" defer="defer"></script>
-<div id="board" data-board=<%s board %> >
 <%s  Format.sprintf "Babillard is love" %>
-</div>
 <div class="row mb-3">
       <div class="col-md-6">
 % begin match Dream.session "nick" request with
 % | None ->
 
 % | Some _nick ->
-%let url = Format.sprintf "/%s/new_thread" board in
-<a href=<%s url %>>[New Thread]</a>
+<a href="/babillard/new_thread" >[New Thread]</a>
 % end;
 <div id="map"></div>
 <button onclick="geolocalize()">Geolocalize me</button>