handle @fastify/x names to export

[Uzlopak]

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[jsumners]

What is this solving?

[Uzlopak]

Before we had e.g. fastify-kafka as module name which was automatically changed to the named export fastifyKafka So it was basically generating module.exports.fastifyKafka = plugin

We renamed all fastify own modules to the form @fastify/x-y-z. So now the named exports are '@fastify/xYZ' which is equivalent to module.exports['@fastify/xYZ'] = plugin.

If the current behaviour is correct, than we have to rewrite the failing test in fastify/fastify-kafka#69 accordingly. If not, we have to merge this, and then the test in that PR will pass.

[climba03003]

LGTM.

[Uzlopak]

@zekth you want to review again?
@jsumners do you have further questions?