less verbose SFTP sync job

Currently, when syncing the SFTP directories, the sync job echoes all file names that are found in the source directory.

IMO it should only echo files that do not yet exist in the target directory. Otherwise the cron-scheduler logs become unreadable.

E.g. there were 12319 output lines in the last 10 minutes

root@tsm:/home/tsm-orchestration/tsm-orchestration# docker compose logs cron-scheduler --since 10m | wc -l
12319

Maybe we could completely skip printing out the file names and just print out something like:

12319 files found in source directory
12000 matching files found in target directory
syncing 319 files