The iso8601_micro and iso8601 facts incorrectly called now.utcnow(), resulting
in a new timestamp at the time it was called, not a conversion of the previously
stored timestamp.
Correct this by capturing the UTC timestamp once then calculating the local
time using the UTC offset of the current system.
* Use time.time() for getting the current time
* Convert from that stored epoch timestamp to local and UTC times
* Used existing timestamp for epoch time
* Add unit tests that validate the formate of the return value rather than an exact value since mocking time and timezone is non-trivial
