chore: Remove unused modules and update metadata.rs (#199)

src-tauri/src/nostr/utils.rs

@@ -0,0 +1,5 @@
+use nostr_sdk::Event;
+
+pub fn get_latest_event(events: &[Event]) -> Option<&Event> {
+  events.iter().max_by_key(|event| event.created_at())
+}