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

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`