Warn on unknown configs

[wraithgar]

This PR will:

• Make npm log a warning when it is parsing a config item that is not defined.
• Make npm log a warning when it is expanding abbreviated config items.
• Warn when an unknown cli flag is making what the user may have intended as a config value be parsed as a positional arg.
• Move nerf-dart configs that were originally hard coded in the npm config command into @npmcli/config for reuse.
• Update nopt to 8.1.0 which has the new features needed to implement these new warnings for cli flags.

[Tayvon]

LGTM!

[ljharb]

Can there be a config to silence these warnings?

[wraithgar]

No there will not. This is an important warning that npm is doing something unexpected. The only place this will likely remain a permanent warning and not an eventual exception is publishConfig because that is ostensibly something other package managers may use. cli flags and npmrc files are not for parsing by things that aren't npm. The warnings from publishConfig will likely change to a "this is being ignored" message when we move to fully disallowing undefined configs, but it will always be there. npm has no way of knowing what in there is legitimate or a mistake so it will always warn.

[ljharb]

I agree that anything in npmrc or cli flags is npm's sole purview, and warnings make sense - but things in package.json aren't and they often won't.