Add a whip check method on ministerial_role.rb

`Whitehall::WhipOrganisation` is used to define the Regex's that are
used to find whips for each psudo org.

We then extract the whip appointments and append them to the orgs list
grouped by whip_organisations sorted by seniority.

ActiveRecordLikeInterface now includes ActiveModel::Conversion and
implments model_name so that content_tag_for method works.