NG: Use legacy navigation until the new linktree element will be ready

Author: amotl

src/crate/theme/rtd/crate/sections/sidebar-primary.html

@@ -4,7 +4,7 @@
 
       <!-- Section 1 -->
       <div class="sidebar-tree">
-        {{ ng_navigation_tree }}
+        {# {- ng_navigation_tree } #}
       </div>
 
       <!-- Section 2 -->