Update images behaviors and model for revised time property parsing

*Added parsing of the created_at and updated_at values to image model
*Added get_image_creation_offset method to images behaviors
*Updated method to get creation offset more generic
*Changed get_creation_offset method to static method

Change-Id: I182f172fd923726d919ce48c41cfeb01b921a96d
Merge "Update images behaviors and model for revised time property parsing"