Student Notes UI

This work is for [TNL-932] (https://openedx.atlassian.net/browse/TNL-932)

@polesye Ping me with any questions, please.

CC'ing @talbs @explorerleslie 
Currently we use the following time format https://github.com/edx/edx-platform/blob/master/common/djangoapps/util/date_utils.py#L18 . So, I guess, we should continue to use it.