Migrate to V3

[scaljeri]

This is a complex one, because it will not be possible to inject the code the same way we do in V2. It is only possible to inject a file. The problem with this is that injecting a file is way slower than injecting javascript directly. And because of this, early XHR/FETCH calls will be missed. The solution is to patch window.Response and other properties of XMLHttpRequest.

More investigation for this is needed!