Add a "Moving" status filter

Because sometime (when your save and download path are on different drives, when your disk drive is super busy, ...) move operations can stack up, I add this "Moving" status filter so you can see in a blink of the eye which torrents are in a move state.

PR #17810.

src/base/bittorrent/torrentimpl.h

@@ -145,6 +145,7 @@ namespace BitTorrent
         bool isForced() const override;
         bool isChecking() const override;
         bool isDownloading() const override;
+        bool isMoving() const override;
         bool isUploading() const override;
         bool isCompleted() const override;
         bool isActive() const override;