RFC: List required permissions for WebUI, Hammer CLI, and Foreman API examples

[maximiliankolb]

basic question: do we want to have a list of required user permissions/roles prior to every procedure?

question for a specific API call was raised by Anet: #3336 (review)

I consider this quite some work to do it right/do it consistently. I suggest to close this issue and do nothing but accept/ask for permissions on individual PR that extend individual procedures with requires user permissions/roles.