create protocol interactively

[hansvancalster]

This PR is an attempt to address #117.

• makes use of checklist::use_author() for author, reviewerand file_manager fields in YAML.
• imports some cli functions for a better user experience when running the function interactively
• added a unit test which uses testthat::local_mocked_bindings() to deal with non-interactivity when running the create_protocol function inside a unit test

I think the function works, but still a lot that needs to be done because the change will break some other functions and unit tests.

[hansvancalster]

@ThierryO thanks for review. I will address some of your comments later, my current most pressing problem is fixing the failing test. I believe they will be fixed by https://github.com/inbo/checklist/pull/117. Can you have a look at that PR?

[ThierryO]

Do you generate a _bookdown.yml for every protocol?

[hansvancalster]

Do you generate a _bookdown.yml for every protocol?

Yes