[BE] Find a way to have less verbose Swagger comments #90

Changes:

Every Swagger comment of controllers and models moved to new dummy classes. You can find them in App\Annotations\OpenApi.
Controllers annotations path: App\Annotations\OpenApi\controllersAnnotations.
Models annotations path: App\Annotations\OpenApi\modelsAnnotations.
To add new Swagger comments/annotations separately from controllers/models, you need to create a new dummy class. IMPORTANT: Swagger comments for dummy functions MUST be named the same as the original function.

IT-Academy-BCN / ita-landing-backend