Accepting field should read "True, False, Not available"

[GovInTrenches]

If we have a shelter added that we don't have information - this defaults to 'false' - when we go to update it - it then enters a zero which the API reads as true.

We need to put in something that shows a N/A and display that status on the map until we confirm otherwise.

[nihonjinrxs]

Went with "true", "false" and "unknown" for the DB values, translating to "Yes", "No", and "Unknown", respectively on the form. PR incoming.