Make account transfer logs uniform

As a web-hosting provider, I would like cpanel account transfer logs to use the same format for all lines, so that I can detect errors in a more reliably.

Currently cPanel stores the details for account transfers in files that are accesible with whmapi1, and we use these files to detect transfer errors. We can detect mysql transfer errors with main.log but for rsync errors we have to use /var/cpanel/transfer_sessions/$SESSIONID/item-RESTORE_AccountRemoteRoot_$USERNAME

This file contains a mix of JSON lines and raw text lines. It would be more reliable if all lines used the same format.

For example :

{"indent":0,"pid":15851,"contents":{"msg":["receiving incremental file list\n"]},"partial":0,"type":"out"}

rsync: send_files failed to open "/home/$USERNAME/.lscache/.cm.log": Permission denied (13)
rsync: opendir "/home/$USERNAME/public_html/folder/-" failed: Permission denied (13)
{"contents":{"msg":["…1 % …\n"]},"partial":0,"indent":0,"pid":15851,"type":"out"}

I believe all lines should use the same format (all json preferably)