Provide quiet option to S3 provider

[BanzaiMan]

Users may end up uploading thousands of files, which will eat up log
capacity.

[BanzaiMan]

This could be a useful option for other potentially noisy providers, but we'll start from here.

[cotsog]

This is great! Thanks!

[soulim]

@BanzaiMan thanks a lot for adding this option. Have you considered a common option for all providers and not just S3? Then it would allow consistent behaviour for all providers.

If I'm not mistaken it should be enough to add conditional logging in this line:

dpl/lib/dpl/provider.rb

Line 294 in 2f13fca

$stderr.puts(message)

Something like this:

def log(message)
  $stderr.puts(message) unless options[:quiet]
end

[BanzaiMan]

@soulim I have not considered it. It could work, but I am afraid that doing so without examining each deployment provider's behavior could make diagnosis hard when problems arise.

[BanzaiMan]

Maybe we should choose a different name for this option. Say, display_uploaded_files: false, with the default being true.

[BanzaiMan]

I didn't mean to do that.

[BanzaiMan]

See #882 for further discussion.