Arvados

Branch 10968-arvput-resume-progress at: ef328d9
Test run: https://ci.curoverse.com/job/developer-run-tests/154/

1. The expected_bytes calculation (when there are a lot of files on disk to be uploaded)
2. If resuming a partial upload, arv-put will check if there's some previously uploaded file on the cached collection that is not on disk on the current run. This was taking too much time, and was fixed on #10932

The updates on this branch include an optimization on the progress reporting and a message to notify the user when it's calculating the expected_bytes count on a potential big file list.
The optimization on progress reporting is about disabling unnecessary checkpointing when the upload hasn't started yet, and using the skipped_bytes count to show a progress indication with the said count vs total.
The final effect is that when resuming, the progress indicator will start from 0% to whatever percentage was left on the previous run, updating every second to provide maximum feedback until the real upload begins, changing to "checkpointing mode" every minute like before.

LGTM, thanks! (Might as well fix errant space at EOL in comment, though... Coding Standards)