Fix Webpack Configuration and Update Dependencies

[Losses]

Problem

The rust-webpack-template repository has not been updated for five years, resulting in a template that fails to create a functional project. This is a critical issue as users following the official documentation end up with completely non-working projects, severely damaging the credibility of this repository.

Changes

This Pull Request addresses these critical issues by:

1. Fixing all Webpack configuration problems to ensure the template works properly
2. Updating most dependencies to their latest versions to ensure compatibility with current toolchains
3. Ensuring the scaffolded project can be built and run successfully out of the box

Why This Matters

Having a non-functioning template as the primary entry point for users creates a terrible first experience and undermines trust in both this repository and the Rust+WebAssembly ecosystem. This PR restores functionality and provides users with a working modern development environment which matches the promises in the documentation.

[Losses]

@Pauan Hey! Would you like to review this pull request?

[Pauan]

@Losses Sorry, I'm not a part of the Rust Wasm team anymore, so I don't have permission to merge this.

Personally I use Rollup for my Rust projects, I use this plugin.

[Losses]

@Pauan Thank you for the suggestion!