Add pedigree information to germplasm endpoint

[dlebauer]

the files contrib/germplasm/season_1_lines.csv has pedigree information. Need to figure out how this information can be stored in the BrAPI germplasm model and then add it to germplasm.json.

Can also consider putting some of the categorical phenotypes (e.g. color, photoperiod sensitivity) into an appropriate endpoint; perhaps easiest would be in traits, except that traits isn't designed to store categorical data and therefore perhaps could go in a separate observations.json file (or attributes table in BETYdb).

Common name information in commercial_hybrids can also used to replace the commonname field in germplasm.json for these lines (currently this is the same as the accession name).