Improve the progress reporting look and feel

• use shortened values in the progress bar (eg. '11.3M/566M' instead of something like '11310201/566123456')
• reduce the description strings and align them.

The result looks like:

Exporting release:

• Offset: 100%|███████████████████████████████| 64/64 [00:03<00:00, 18.61it/s]
• Export: 100%|█████████████████| 130/130 [00:01<00:00, 10.3it/s, workers=4/4]