Replace oscn with courtbot on courtbot-python

[syk1112]

About this Issue

Here are all the ways oscn library is used on the codefortulsa/courtbot-python:
Used in api/views.py
Get case using:

  case = oscn.request.Case(year='2018', number=case_num)

Get araignment event from the case using:

  find_arraignment_or_return_False(case.events)
  which checks for `"arraignment"` in `event.Docket.lower()`

Get eligible jurisdictions using:

  oscn.Counties

Get datetime of the event's arraignment date:

  # where event = arraignment_event.Event
  event = event.replace('ARRAIGNMENT', '').rstrip()
  return datetime.strptime(event, "%A, %B %d, %Y at %I:%M %p")

We should replace these references to oscn to the new courtbot library.