Resolve "add delete datafile api endpoint"

Closes #136 (closed)

import requests
url = 'http://localhost:8000/api/v1/datafiles/json/delete/DF00000000'
headers = {'Iric-Auth-Token': '123xyz123xyz123xyz123xyz123xyz123xyz123xyz123xyz123xyz123xyz'}
r = requests.delete(url, headers=headers)
r.json()