CSV importer initial commit, some model changes, new migration

Example first row of column headers from a CSV:

original_name,title__en_US,formatted_name,standard_name,description__ka,description__en_US,phase,entity,Group,allowable_values,data_type,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,