Generating structs based on the typescript types from the official JS sdk

[jhchabran]

After going back and forth on #9, it feels like making sure the API reference is properly implemented is a quite meticulous task that is quite error prone and may introduce vicious bugs that will be hard to track down.

The official JS SDK has all the API types properly defined in Typescript, which could be used to generate those structs: https://github.com/makenotion/notion-sdk-js/blob/main/src/api-types.ts

An example on how to achieve that can be found in gopls, which uses that approach to handle the structs that deals with the Language Server Protocol: https://github.com/golang/tools/tree/master/internal/lsp/protocol/typescript

I may give it a try in the upcoming days, I'll post here if I do!