Make setup/teardown_authorization standalone functions
Make setup/teardown_authorization standalone functions

Keeping them as methods on BaseApplicationTest makes it harder
to reuse the logic for non-class-based tests.

RichardKnop/digitalmarketplace-search-api,RichardKnop/digitalmarketplace-search-api,RichardKnop/digitalmarketplace-search-api,alphagov/digitalmarketplace-search-api,RichardKnop/digitalmarketplace-search-api,alphagov/digitalmarketplace-search-api