Include treatment info in phenotype download files

[bellerbrock]

Expected Behavior

From Raul at CIP:

Treatments are visible when we download the layout (Download Layout in the Experimental Design section) but not when we download the data (Download Trial data in the Phenotype Summary Statistics section). So, for a user downloading the data from sweetpotatobase I think the treatment structure can go unnoticed.

For Bugs:

Environment

Steps to Reproduce