Add a script that generates the .d.ts files based on current documentation

[NuriYuri]

Supposedly fixes #340

I've noticed that openapi-generator-cli was making a file with class names that do not match some of the exported classes. The documentation in the other hand is quite accurate, it just have few issues like inconstant case style.

With that in mind I decided to write a tiny script that converts the documentation to a .d.ts file. I think it's a decent alternative while waiting for actual typescript definition or bigger fixes in the code to have classes that matches the open-api docs :)

[youssef-saber-3]

Hey, we took a look at the PR and we appreciate the effort you put into it but at the moment we don't want to rely on the .md files to generate the types because they weren't intended for that purpose and they might break in the future. and if we decided to go with that approach we unfortunately don't use ruby so it would be tricky to maintain this code in the future if we commit it

we're currently working towards doing a general release of the typescript client soon which would alleviate this issue. thank you for putting the effort into it, it's much appreciated