feat: add AccountsChanged and AccountsItemChanged events (#6118)

- **feat: add `AccountsChanged` and `AccountsItemChanged` events**
- **emit event and add tests**

closes #6106

TODO:
- [x] test receiving synced config from second device
- [x] bug: investigate how to delay the configuration event until it is
actually configured - because desktop gets the event but still shows
account as if it was unconfigured, maybe event is emitted before the
value is written to the database?
- [x] update node bindings constants

src/tests.rs

@@ -1,2 +1,3 @@
+mod account_events;
 mod aeap;
 mod verified_chats;