smp server: combine messages and queue storage to optimise performance, prevent race condition when deleting queue and to avoid "orphan" messages. (#1395)

* smp server: combine queue and message store into one class (WIP)

* keep deleted queue tombstones to prevent race conditions and errors when restoring

* move store log from server to store implementations

* STMQueueStore type class

* fix store closed when messages expired, handle store writing errors

* types

* version

* fix recovery from missing write journal, tests

* version

src/Simplex/Messaging/Notifications/Server.hs

@@ -115,10 +115,12 @@ ntfServer cfg@NtfServerConfig {transports, transportConfig = tCfg} started = do
 
     stopServer :: M ()
     stopServer = do
+      logInfo "Saving server state..."
       saveServer
       NtfSubscriber {smpSubscribers, smpAgent} <- asks subscriber
       liftIO $ readTVarIO smpSubscribers >>= mapM_ (\SMPSubscriber {subThreadId} -> readTVarIO subThreadId >>= mapM_ (deRefWeak >=> mapM_ killThread))
       liftIO $ closeSMPClientAgent smpAgent
+      logInfo "Server stopped"
 
     saveServer :: M ()
     saveServer = withNtfLog closeStoreLog >> saveServerLastNtfs >> saveServerStats