Only publish profile when something has changed

Currently the profile os published every time:

```
Publishing profile (Kind 0)...
  nsite:nostr relays to broadcast to: [
  'wss://purplepag.es/',
  'wss://user.kindpag.es/',
  'wss://nos.lol/',
  'wss://relay.primal.net/',
  'wss://relay.nostr.band/',
  'wss://relay.damus.io/'
] +11ms
  nsite:nostr profile posted to 5 relays +3s
```

The profile should only published when some data has changed.