Add webpack as optional peer dependency

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### Feature Proposal

Rspack use webpack-dev-server internally to compatible with devServer functionality but it will cause install warning because lack of webpack. see https://github.com/web-infra-dev/rspack/issues/2318

```sh

└─┬ @rspack/cli 0.1.1

  └─┬ @rspack/dev-server 0.1.1

    ├─┬ webpack-dev-server 4.11.1

    │ ├── ✕ missing peer webpack@"^4.37.0 || ^5.0.0"

    │ └─┬ webpack-dev-middleware 5.3.3

    │   └── ✕ missing peer webpack@"^4.0.0 || ^5.0.0"

    └─┬ @rspack/dev-middleware 0.1.1

      └─┬ webpack-dev-middleware 6.0.0

        └── ✕ missing peer webpack@^5.0.0

Peer dependencies that should be installed:

  webpack@">=5.0.0 <6.0.0"

```

we are wondering whether webpack-dev-server could list webpack as optional peer dependency to help avoid this warning in rspack

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### Feature Use Case

support use webpack-dev-server in rspack

### Please paste the results of `npx webpack-cli info` here, and mention other relevant information

none

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