[error-utils] Create @vercel/error-utils package (#8828)

While working on #8742 i found some useful error checking code buried in
the CLI. This PR adds a new private package `@vercel/errors` that moves
those helpful utilities into its own package so it can be used
throughout the monorepo.

packages/cli/src/util/output/create-output.ts

@@ -2,7 +2,7 @@ import chalk from 'chalk';
 import renderLink from './link';
 import wait, { StopSpinner } from './wait';
 import type { WritableTTY } from '../../types';
-import { errorToString } from '../is-error';
+import { errorToString } from '@vercel/error-utils';
 
 const IS_TEST = process.env.NODE_ENV === 'test';