log-writes: add replay-log program to replay dm-log-writes target

Imported Josef Bacik's code from:
https://github.com/josefbacik/log-writes.git

Specialized program for replaying a write log that was recorded by
device mapper log-writes target.  The tools is used to perform
crash consistency tests, allowing to run an arbitrary check tool
(fsck) at specified checkpoints in the write log.

[Amir:]
- Add project Makefile and SOURCE files
- Document the replay-log auxiliary program
- Address review comments by Eryu Guan

Cc: Josef Bacik <jbacik@fb.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

doc/auxiliary-programs.txt

@@ -18,6 +18,7 @@ Contents:
  - af_unix		-- Create an AF_UNIX socket
  - dmerror		-- fault injection block device control
  - fsync-err		-- tests fsync error reporting after failed writeback
+ - log-writes/replay-log -- Replay log from device mapper log-writes target
  - open_by_handle	-- open_by_handle_at syscall exercise
  - stat_test		-- statx syscall exercise
  - t_dir_type		-- print directory entries and their file type
@@ -46,6 +47,13 @@ fsync-err
 	writeback and test that errors are reported during fsync and cleared
 	afterward.
 
+log-writes/replay-log
+
+	Specialized program for replaying a write log that was recorded by
+	device mapper log-writes target.  The tools is used to perform crash
+	consistency tests, allowing to run an arbitrary check tool (fsck) at
+	specified checkpoints in the write log.
+
 open_by_handle
 
 	The open_by_handle program exercises the open_by_handle_at() system