Add tabnav, dedicated auths view to RS service page

Includes a nicer view and illustration for when no auths exist yet

app/views/services/rs_auths/index.html.erb

@@ -0,0 +1,33 @@
+<%= render HeaderComponent.new(title: "Storage") %>
+
+<%= render MainSimpleComponent.new do %>
+  <section>
+    <p class="mb-6">
+      Store and synchronize your app data across different devices.
+    </p>
+  </section>
+
+  <%= render partial: "shared/tabnav_remotestorage" %>
+
+  <section>
+    <% if @rs_auths.any? %>
+      <div class="w-full grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-y-10 gap-x-12 mt-4">
+      <% @rs_auths.each do |auth| %>
+        <%= render RsAuthComponent.new(auth: auth) %>
+      <% end %>
+    </div>
+    <% else %>
+      <div class="text-center">
+        <p class="mt-4 mb-12 inline-flex align-center items-center">
+          <%= image_tag("/img/illustrations/undraw_friends_r511.svg", class: 'h-48') %>
+        </p>
+        <h3>
+          No apps connected
+        </h3>
+        <p class="text-gray-500">
+          When connected, your apps will show up here.
+        </p>
+      </div>
+    <% end %>
+  </section>
+<% end %>