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/events/payload.rs

@@ -344,6 +344,20 @@ pub enum EventType {
         chat_id: Option<ChatId>,
     },
 
+    /// Inform that the list of accounts has changed (an account removed or added or (not yet implemented) the account order changes)
+    ///
+    /// This event is only emitted by the account manager
+    AccountsChanged,
+
+    /// Inform that an account property that might be shown in the account list changed, namely:
+    /// - is_configured (see [crate::context::Context::is_configured])
+    /// - displayname
+    /// - selfavatar
+    /// - private_tag
+    ///
+    /// This event is emitted from the account whose property changed.
+    AccountsItemChanged,
+
     /// Event for using in tests, e.g. as a fence between normally generated events.
     #[cfg(test)]
     Test,