Move development docs to GitHub Wiki

[elisee]

We should move everything in https://github.com/superpowers/docs.superpowers-html5.com/tree/master/pages/en/4_development to a wiki at https://github.com/superpowers/superpowers/wiki

Those docs are developer-oriented and don't need to be translated, and they belong on the repository itself. We should replace the existing pages in the documentation with a link to that wiki.