Support ESLint Flat Config

[ModyQyW]

closes https://github.com/nuxt-modules/eslint/issues/115

1. replace vite-plugin-eslint with vite-plugin-eslint2, which supports flat config, active and maintained by me
2. Just set eslintPath: 'eslint/use-at-your-own-risk' and eslint.config.js, and flat config should be done

While it would be possible to auto-detect to determine the ESLint version and whether to enable flat config by default, I think this would add unnecessary complexity. I will add this function to the PR if you think it's worth it. Thank you.

[ModyQyW]

For someone who comes here later, try https://eslint.nuxt.com/ instead.