fix circular dependencies

Because of them, I have to put all of this package code in a single file

readings :
- https://medium.com/visual-development/how-to-fix-nasty-circular-dependency-issues-once-and-for-all-in-javascript-typescript-a04c987cf0de
- https://spin.atomicobject.com/2018/06/25/circular-dependencies-javascript/

usefull command : 
- npx madge --circular --extensions ts ./ 