Do not add Timezone attribute to the data set.

If the meta data already has time attributes that are not in the
local timezone, this would cause them to be incorrect.  Also, very
few DICOM images seem to have Timezone info.
Do not add ContentDate or ContentTime if not already present.

The DICOM standard (PS 3.3) says that these attributes are required
if the images in the series are temporally related to each other.
The generator cannot make that decision, and giving all of the images
in the series the same ContentTime  does not make sense.