[Feature]: add templates for Nestjs project

[ianzone]

What problem does this feature solve?

wonder if it's more concise to use rsbuild for nestjs projects than rspack.

What does the proposed API look like?

add a description page on the framework section.

[chenjiahan]

At this stage, Rsbuild is more focused on building web applications. For Node.js applications such as Nest.js, we currently have no plans to provide first-party support in Rsbuild, but I believe this can be achieved through a community-maintained Rsbuild plugin.