Add command-line arguments for hackage username and password in upload

[sergeykolbasov]

Hi there

I think it would be meaningful to have following command line arguments available for stack upload command:

--hackage-username=$username
--hackage-password=$password

Those arguments if set should replace credentials file or user prompt. I think it'll simplify upload to Hackage from CI/CD environment where $username and $password could be stored in env variables.

If people find it useful, I could land a PR:

• Add parser for Stack.Options.UploadParser that includes SDistParser and optional parameters hackage-username and hackage-parser
• If both parameters are presented, these are used as HackageCreds for upload