CerberusClient has commented out methods

[Relativiteit]

It seems that the a few methods in this Client are not possible to run due to some typo's in the client. And in doing so the methods are not able to be called. The following methods are not accessible at the moment.

• async _executeRequest
• async _doFileAction
• async _getToken

I will try to make the changes, test the function and raise a PR unless someone else already has a fix for this.