Add function for determining if an organisation is an NDPB.

There are three OrganisationType object that are Non-Departmental Public
Bodies, it is useful to determine if a given organisation is one of
those.
Import additional data from Public Bodies report.

Adds Public Meetings, Public Minutes, OCPA Regulated, Regulatory Function

Add a migration to add fields to an Organisation.  Update the public
bodies rake task to import relevent data.

Update schema to keep it up to date.
Add fields to Organisatons to edit NDPB data.

If an organisation is a Public Body, ask for optional data on Public
Meetings, Public Minutes, OCPA Regulated, Regulatory Function

Options can be blank as not all NDPBs publish this data and we cannot
assume Yes or No for bodies that haven't given an answer.
Correctly indent 'end' in is_ndpb?
Merge pull request #767 from ElliotJH/import-pb-yes-no-data

Import further data from Public Bodies Report