Create a way to customize ng-new

### Command

new

### Description

for workshops it would be helpful to have a customized start screen with custom html to make it easier for people to start the workshop and have less friction with updated start view with newer versions as e.g. with v17 happened

### Describe the solution you'd like

a configuration which provides a reference to a custom template of a start screen, e.g.

ng new todo-list --start=@ng-girls/starter

and for this there need to be a special scheme to configure the start template or other options

### Describe alternatives you've considered

stackblitz, but I would also have it with the CLI

Comienza con el punto de entrada del comando ng new y determina cómo se definen las opciones del comando y la configuración del proyecto. El ejemplo del issue es ng new todo-list --start=@ng-girls/starter; la implementación debe incluir un esquema definido para seleccionar una plantilla de inicio personalizada y aclarar las opciones de configuración compatibles.

Escrito por el modelo de indexación a partir del texto del issue.