Add add the first unit test for fm-rest-api/fm/fm/common/timeutils.
Add tox task for py27/35 as zuul checking and gating jobs.
Story: 2007082
Task: 38077
Change-Id: I2f259dcf2178f42546966063c0d724bc17e2a804
Signed-off-by: chenyan <yan.chen@intel.com>