This introduces a heap of changes from our API spreadsheet and consequently fixes the mock application.
I didn't update any tests because we have an issue open to migrate away from the pytest-bdd suite.
https://govstack-global.atlassian.net/browse/CON-180?atlOrigin=eyJpIjoiNGIyYmRmZWQxZjY0NDM2Y2FkZGY2MGU3NjA5M2U5YjMiLCJwIjoiaiJ9