feat: code splitting base on directives

[huozhi]

Split module with "use client" and "use server" directives into different chunks, so that bundler can the boundaries are controlled as minimum size. When they're integrated to the app like Next.js, the bundler can analyze the boundaries properly and transform into properly client components or server actions modules

[lovrozagar]

When using bunchee -m, minification removes the directive at the top of the file, components with "use client", after building, become server components even though they are separated into a x-client.js file. Works fine when using just bunchee without minification.

[nnecec]

What does the prependDirectives plugin do? It looks like the rollup-preserve-directives plugin collects directives and prepends directives at the render phase.

According to the rollup-plugin-swc3 documentation, rollup-preserve-directives should be used after swc3, it'll fix the -m problem.

[huozhi]

@nnecec if the module is marked as certain type, we need to append the directive, that's what prependDirectives is doing.
We can carry on the discussion in #462