validate timeseries new fields

[antgonza]

From previous discussion in the Knight Lab mailing lab:

• Single treatment event (STE): This are the cases when there is only 1 event. For example, the mice decomposition study. The solution is to extend the current mapping file with the following fields:
  timestamp_sample (MM/DD/YYYY HH:MM:SS, local time)
  timestamp_treatment_start (MM/DD/YYYY HH:MM:SS, local time)
  timestamp_treatment_end (MM/DD/YYYY HH:MM:SS, can be empty)
  desc_treatment
  epoch_time (automatically added in the DB)
  epoch_since_treatment (automatically added in the DB)
• Multiple treatment event (MTE): For those cases that we have several interventions. For example, the Bangladesh travel or mouth experiment. For this we will use an external "mapping" file with these fields:
  host_subject_id
  event_desc
  event_date_start (MM/DD/YYYY HH:MM:SS, local time)
  event_date_end (MM/DD/YYYY HH:MM:SS, local time)