Generate relative path for types

[huozhi]

This PR refactors each build to a standalone rollup build job including its own input and own output, instead of having one input and multi output before.

For .d.cts and .d.mts we need to import the proper file, for instance, .d.cts matches .cjs files and .d.mts matches .mjs files, so you would have:

In a .d.mts file, module resolving situation will be like

// index.d.mts
export { Shared } from '../shared/index.mjs'; // ✅
export { Shared } from '../shared/index'; // ❌ cannot resolve
export { Shared } from '../shared/index.cjs'; // ❌ cannot resolve

This means we need a resolving map for each format of build, if we're building import condition output with esm syntax format, we need to alias the code to mjs output. This rule only applies to types. JS can still do <pkg>/<export> import as nodejs is able to resolve that.

So we created alias for each build, and also put relative path there to make sure they can be resolved

Resolves #390