Add quiet mode

[udf2457]

For use in scripts, it would be nice to have a "quiet mode" (i.e that only outputs to stderr on error rather than the more verbose present style)

[tjprescott]

The CLI is already designed to be quiet. What verbose style are you referring to? A specific command?

[udf2457]

I'm more referring to the typical Linux definition of quiet (i.e. only make noise if there's something wrong).

For example, you would expect az storage blob upload --no-progress to be pretty quiet, but it still blurts out content on success but all I'm really interested in is whether or not the upload was successful, which means at the moment I'm forced to > /dev/null 2>&1

Or the same with a clean-up command such as:
az storage blob delete-batch -s "${azureContainer}" --delete-snapshots include --if-unmodified-since "${timeDelta}"

I don't really care for output if the clean-up was succesful, I only want to hear about failures.

[mattbits]

duplicate of #5667

[yonzhan]

add to S165.

[jiasli]

We have added option --only-show-errors in #12604 to disable warnings that are written to stderr. It will be included in S167 release.