Add arguments to the upload data & logs commands to only upload a chunk of the data & log files

[dajtxx]

The nodes are struggling to upload the entire log & data files, plus this is a big data soak.

Change these commands to allow a chunk of offset/length, or -length to be specified.

All arguments are in bytes.

offset/length allows an arbitrary chunk of length bytes starting at offset of the file to be uploaded.

-length means the last length bytes of the applicable file.