Add --no-output argument

[jcs090218]

Refer to https://github.com/sherlock-project/api/pull/2#issuecomment-814222974.

I think by adding argument --no-output would be a better choice, so the server would not need to delete files afterward.

[jcs090218]

@sdushantha WDYT about this patch?

[sdushantha]

@jcs090218 This seems like a good feature! I'll start working on Sherlock again sometime in late May, early June because this project is not a priority for me at the moment.