Fix torrent checking issues

Start all torrents auto-managed to prevent simultaneous checking
of multiple torrents.
Handle checking state of paused torrent to prevent it from being
resumed when qBittorrent is closed until checking isn't complete.

src/base/bittorrent/torrenthandle.h

@@ -447,12 +447,15 @@ namespace BitTorrent
 
         enum StartupState
         {
-            NotStarted,
-            Starting,
-            Started
+            Preparing, // torrent is preparing to start regular processing
+            Starting, // torrent is prepared and starting to perform regular processing
+            Started // torrent is performing regular processing
         };
+        StartupState m_startupState = Preparing;
+        // Handle torrent state when it starts performing some service job
+        // being in Paused state so it might be unpaused internally and then paused again
+        bool m_pauseWhenReady;
 
-        StartupState m_startupState = NotStarted;
         bool m_unchecked = false;
     };
 }