feat: dragonfly decorator

[ilteoood]

Resolves #184

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

[mcollina]

I don't understand the purpose of this, could you clarify? This seem to only change the name of the decorator.

[ilteoood]

Hi @mcollina,
You are right: the purpose of this is just to define a different decorator name if the user wants to use this plugin with Dragonfly instead of Redis.
My idea behind this is just to improve the DX and avoid the user to type fastify.redis when he's not using Redis, but Dragonfly.

[kibertoad]

@ilteoood This seems to complicate the codebase for questionable benefits. I'm -1 on it.

[Uzlopak]

I think, developers will not get psychologycal damage by typing redis instead of dragonfly.

Also we have the namespace option.

So I am -1

[ilteoood]

Ok then, at least I tried.
Thank you everyone for your time, feel free to close both the PR and the issue then