feat: Super admin design improvements (#8517)

- Revamp the super admin design
- Introduce a new settings page for support and billing settings
- Move the access tokens into users, agent bots and platform app show pages


Co-authored-by: Sojan <sojan@pepalo.com>
Co-authored-by: Pranav Raj S <pranav@chatwoot.com>

app/views/super_admin/application/_nav_item.html.erb

@@ -0,0 +1,9 @@
+<li
+  class="px-4 border-l-4 mb-1 <%= current_page?(url) ? 'border-woot-500' : 'border-transparent' %>"
+>
+  <% text_class_name = current_page?(url) ? 'text-woot-500 bg-slate-25' : 'text-slate-800' %>
+  <%= link_to(url, class: text_class_name + " -ml-1 focus:outline-none cursor-pointer flex items-center px-2 py-1.5 text-slate-800 cursor-pointer hover:text-woot-500 hover:bg-slate-25 rounded-lg") do %>
+    <svg width="16" height="16"><use xlink:href="#<%= icon %>" /></svg>
+    <span class="ml-2 text-sm"><%= label %></span>
+  <% end %>
+</li>