ios, core: better notifications processing to avoid contention for database (#3485)

* core: forward notifications about message processing (for iOS notifications)

* simplexmq

* the option to keep database key, to allow re-opening the database

* export new init with keepKey and reopen DB api

* stop remote ctrl when suspending chat

* ios: close/re-open db on suspend/activate

* allow activating chat without restoring (for NSE)

* update NSE to suspend/activate (does not work)

* simplexmq

* suspend chat and close database when last notification in the process is processed

* stop reading notifications on message markers

* replace async stream with cancellable concurrent queue

* better synchronization of app and NSE

* remove outside of task

* remove unused var

* whitespace

* more debug logging, handle cancelled read after dequeue

* comments

* more comments

apps/ios/Shared/Model/ChatModel.swift

@@ -105,11 +105,13 @@ final class ChatModel: ObservableObject {
     static var ok: Bool { ChatModel.shared.chatDbStatus == .ok }
 
     var ntfEnableLocal: Bool {
-        notificationMode == .off || ntfEnableLocalGroupDefault.get()
+        true
+//        notificationMode == .off || ntfEnableLocalGroupDefault.get()
     }
 
     var ntfEnablePeriodic: Bool {
-        notificationMode == .periodic || ntfEnablePeriodicGroupDefault.get()
+        notificationMode != .off
+//        notificationMode == .periodic || ntfEnablePeriodicGroupDefault.get()
     }
 
     var activeRemoteCtrl: Bool {