ui: move logout into the hamburger menu too

static/index.html

@@ -13,10 +13,10 @@
     <input id="q" placeholder="search anime…" autocomplete="off">
   </form>
   <span id="me" class="muted"></span>
-  <button id="logout" class="tiny" style="display:none">logout</button>
   <div id="menubox" style="display:none">
     <button id="menu" class="tiny" aria-label="menu" aria-haspopup="true">☰</button>
     <div id="menu-items">
+      <button id="logout" class="tiny">logout</button>
       <button id="delacct" class="tiny danger">delete account</button>
     </div>
   </div>