Adds support for styleModule

[arcanis]

This PR adds support for the styleModule configuration, a way to change the (currently hardcoded) module that gets imported during the styled-jsx transpilation.

Part 1 of vercel/next.js#10149

[giuseppeg]

@arcanis thanks for the PR! Looking at the issue I wonder if this could be fixed in Next.js by rewriting the import declaration source with a Babel plugin so that it points to the right module or with a webpack alias?

[arcanis]

I think idiomatically the 'right' path should be configurable by the transforms themselves - this is for example what transform-runtime does (kinda) with absoluteRuntime which instructs it to use the absolute path rather than the regular package name. In our case I think it's better for portability to avoid absolute paths and use the Next.js package name instead.

[giuseppeg]

Thank you @arcanis and sorry for the delay! I'll release a minor version