Ability to hide Pages from students

Description

I've added additional setting into the pages config to have an ability to hide pages from the students:
![pages](https://cloud.githubusercontent.com/assets/1876893/16520444/cc86750e-3f98-11e6-8edb-53e8fa1dcf15.jpeg)

Assignee

ChristinaR

Reporter

Edx Admin [Administrator]

Labels

Contributor Name

Dmitry Viskov

Repo

edx/edx-platform

Customer

Epic Link

None

OSCM Assignee

Shauna Gordon-McKeon

Platform Map Area (Levels 1 & 2)

None

Platform Map Area (Levels 3 & 4)

None

Story Points

1

Priority

Unset
Configure