feat: Build & publish type declarations

[sufian-slack]

Hey there, we've instrumented our jest build phases so that we're collecting performance metrics around compilation. To do this, we augment the transform returned by transformSync.

By publishing the types of this package, this wrapping code can be written in typescript without adding some global declarations for @swc/jest:

i.e. we do something like this:

import { createTransformer } from '@swc/jest';
export function createTransformer() {
  const swcTransformer = createTransformer();
  return { ... /* use swcTransformer */ ... };
}

[CLAassistant]

All committers have signed the CLA.