fun addDateTimeStampTag(tag: Exify.TAG, timestamp: long, timezone: java.util.TimeZone): boolean
Creates, formats, and sets the DateTimeStamp tag for one of: {@see #ExifTagKey.DATE_TIME}, {@see #ExifTagKey.DATE_TIME_DIGITIZED}, {@see #ExifTagKey.DATE_TIME_ORIGINAL}.
tag - Exify.TAG: one of the DateTimeStamp tags.
timestamp - long: a timestamp to format.
timezone - java.util.TimeZone: a TimeZone object.
Return
boolean: true if success, false if the tag could not be set.