add glob import section

[hardfist]

          `import.meta` is part of the ECMAScript standard but `require.context` is a webpack-only API.

I just found webpack has supported import.meta.webpackContext and Rspack also supports it: web-infra-dev/rspack#4466

We should document this and recommend users to use import.meta.webpackContext instead of require.context.

Originally posted by @chenjiahan in web-infra-dev/rspack#4986 (comment)

[hardfist]

glob import is frequently used features which needs specific section tell user how to do it in Rspack like vite does https://vitejs.dev/guide/features.html#glob-import