Zstd should try to draw the progress bar only on TTY

[jimis]

I run zstd v1.4.4 as a cron job, and I get a progress bar output even when the stdout and stderr are not tty:

zstd --rm -19 $FILENAME  2>&1 | logger

Zstd tries to draw the progress bar, as a result I see this in the journal:

[386B blob data]

It would be best to imply -q when the stdout/stderr are not a tty. Or at least print \n instead of \r as a separator between the lines.

[terrelln]

I think implying -q when stderr is not a TTY would make sense.