704 | Audit code to ensure all dates are stored in UTC

https://trello.com/c/TvXlpCUz/704-audit-code-to-ensure-all-dates-are-stored-in-utc

Currently dates are stored in database with local time zone.
This change causes that all dates are stored in UTC.

Change-Id: Ifc93d206cff8ce81d232b49d8518403e2e4ce06a
Merge "704 | Audit code to ensure all dates are stored in UTC"