Pass the --dir CLI flag to @netlify/config

[ehmicky]

The deploy and dev commands use a --dir CLI flag, representing the build.publish directory.

This flag should be passed to @netlify/config --inlineConfig.publish {dir}

Those CLI commands should then use the returned config.build.publish value instead of the --dir CLI flag. This is because @netlify/config does more logic to retrieve the publish directory.

[ehmicky]

Some work was started at #1010, but the PR has been closed since.