Dont expose user email via API

To prevent leaking of users info we reduce amount of user information
retrieved via API for normal users.

What user can get via API:

* if not admin: only id, state, name, username and avatar_url
* if admin: all user information
* about himself: all informaion

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>