Towards autoupdating pyfar packages on template changes

[ahms5]

We decided to migrate from Cookiecutter to Copier.
I would suggest to first remove used cookiecutter functionality (#63), next migrate to copier, than add new functionality

1. remove unsed funtionality in cookiecutter remove unused functionality to make the migration to copier easier #63
2. micrate everthing to copier migrate to copier #65
3. add required functionally to use it for automatic pullrequrest to apply changes (see e.g. here [Bot]: apply cookiecutter template pyfar#797)