Added "admins" parameter to the zero config

* A user account can now be added to the json zero config,
  validated and shown properly as a link to the User:xxx page.
* Changed security model - now in addition to 'zero-edit' right which
  gives admin access to zero namespace, any user who has been listed
  in the 'admins' section of the configuration page will have 'edit'
  rights to that page (This affects only that specific config page).
  In order to prevent accidental lockout, when a partner edits config,
  they cannot remove themselves from the 'admins' section.
* Minor cleanup - old sample json file is deleted, comments

Change-Id: I698c85d548c383b044374cd2c44b8baa61b1379f
Merge "Added "admins" parameter to the zero config"