Remove derive_builder as a dependency

[tonymushah]

Hello everyone! I'm sure you all doing well.

Anyway, after a long time of learning and practising Rust, I'm finally decided to remove derive_builder as a dependency.

If you don't know (yet), derive_builder is the library that used to build an endpoint struct.

It was already mentioned by @gondolyr (the old maintainer) and put in #2 for quite some time now, but back then my Rust skills are poor than now.

What's the plan?

• Remove derive_builder on each Cargo.toml
• Make a derive macro that handle this endpoint building for us
• Spend more than it should to refactor each endpoint

Normally, when it's done, it should the same syntax as the one that we use now.