Show date and time on Schedules and Details in UTC (TNL-85).

Make the dates/times on the Schedules and Details page reflect UTC, not the local time. 

Issue: https://openedx.atlassian.net/browse/TNL-85

Sandbox: http://studio.olmar.m.sandbox.edx.org/
Reviewers: @polesye @cahrens 
Done with 24-hour day.