Participation - User roles

[welcoMattic]

From now we will have several roles for users:

• Super admin
  • Can see and act on every Entities in admin
  • Can impersonate a User/Admin
  • Inherit from Admin
• Admin
  • Can see and act on every Entities except Users in admin
  • Can manage Participation demands
  • Can manage sponsoring for Conferences
  • Can login on admin
  • Inherit from User
• User
  • Can login to their profile
  • Can see their stats
  • Can create talks, submit them
  • Can mark a submitted talk as pending/accepted/rejected
  • Can ask for participation to a conference
  • Can cancel a participation demand (until it is accepted)