migrate to class

[sirenkovladd]

migrate to class syntax (Chain, request, response)

copied class from https://github.com/fastify/light-my-request/pull/252 but without changing the logic in lib/do-inject.js (doInject) (to resolve Test Fastify Integration)

Checklist

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

[sirenkovladd]

@jsumners, Can you explain your negative attitude?

[jsumners]

• https://github.com/fastify/light-my-request/pull/252#issuecomment-1700289217
• https://github.com/fastify/light-my-request/pull/252#issuecomment-1700941877
• https://github.com/fastify/light-my-request/pull/252#issuecomment-1701062425
• https://github.com/fastify/light-my-request/pull/252#issuecomment-1781074509

[sirenkovladd]

@jsumners I'm not mentioning bun in this PR (since not all issues are resolved) what happens in this PR is the grouping of the function into a class (it was already there, but it was Function.constructor I go to the class syntax) on the contrary, it will be easier to maintain