text: Title: Implement permission management on admin for post editing
  Body: Suggested by @matheusbrat
  
  > is it possible to apply a prefilter on quokka admin? For example, a editor could see just his publications instead of all?
  
  Desired functionality
  1. Admin can see/edit everything
  2. On role create it should be possible to define if the role sees everything or only things under its own domain
  3. It should be possible to put roles under roles (and child should follow the parent rules)
  4. On content creating (channel and posts) should be possible to select edit permission 
     
     [ ] Editable by any user 
     [ ] editable by specific roles 
     [ ] Editable by specific authors 
     [ ] editable only by creator
  5. Apply the same for visibility
  6. Visibility is on quokka.core.views
  7. Admin is under Admin models (we should override some admin methods)
  