Feature/altres altes
This MR should bring following features (quoting from specs):
- desaparecer pantalla bienvenida
- revisar "necessita cobertura legal" [drop]
- posibilidad de añadir socies afins a posteriori
- retocar 12h y 24h por 6h y 12h
- libros integrales en csv
Please remember to apply the migrations on server.