WIP: Improve Nostr user metadata fetching

Use a multi-step process, caching results in between, while informing
the user about the current steps/progress

app/views/settings/_nostr.html.erb

@@ -88,8 +88,15 @@
   </section>
 
   <% if current_user.nostr_pubkey.present? %>
-    <%= turbo_frame_tag "nostr_user_metadata", src: nostr_user_metadata_settings_path do %>
-      <p>Loading...</p>
-    <% end %>
+    <div data-controller="nostr-metadata"
+         data-nostr-metadata-url-value="<%= nostr_metadata_settings_path %>">
+      <div data-nostr-metadata-target="loading"
+           class="flex flex-col items-center justify-center py-16">
+        <div class="mb-4 h-12 w-12"></div>
+        <p data-nostr-metadata-target="status"
+           class="text-gray-500 animate-pulse">Loading…</p>
+      </div>
+      <div data-nostr-metadata-target="content" class="hidden"></div>
+    </div>
   <% end %>
 </div>