feat: add new endpoint for structures, data is formated (jointure on modules)

src/admin/admin.controller.spec.ts

src/app.module.ts

src/categories/categories.module.ts

src/migrations/scripts/1617962328658-add-newsletter-data.ts

src/structures/services/structures.service.ts

src/structures/structures.controller.ts

src/users/users.controller.spec.ts