i18n support for urfave/cli

[coilysiren]

What problem does this solve?

We have many users of this CLI from all over the world, so it may be useful to provide translations for our error messages? Possibly ones that default to the language set by the user's environment variables? That would likely make the CLI easier to use for them.

Solution description

This is more-so a discussion and idea generation issue, rather than an explicit feature spec.

[stale[bot]]

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[meatballhat]

Yes please

[meatballhat]

I'm moving this to target 3.x given the expected scope.