[Feature Request] Provide completion list for default settings via the "az configure" command

[lostintangent]

It would be awesome if this extension provided a completion list for valid setting names when typing az configure --defaults (e.g. web, location, group, acs). The CLI itself doesn't even provide this information in a single place, or in the help text for the az configure command (since --defaults isn't an enum property), so that may be a feature request for the CLI. However, I tend not to use completion in the CLI, so the feature "feels" more useful in the context of this extension :)