Add first version of POST endpoint to create a brief
Add first version of POST endpoint to create a brief

alphagov/digitalmarketplace-buyer-frontend,alphagov/digitalmarketplace-buyer-frontend,AusDTO/dto-digitalmarketplace-buyer-frontend,AusDTO/dto-digitalmarketplace-buyer-frontend,AusDTO/dto-digitalmarketplace-buyer-frontend,AusDTO/dto-digitalmarketplace-buyer-frontend,alphagov/digitalmarketplace-buyer-frontend,alphagov/digitalmarketplace-buyer-frontend