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

從 ng new 命令的入口點開始，確定命令選項和專案設定是如何定義的。Issue 中的範例是 ng new todo-list --start=@ng-girls/starter；完成的實作應包含用於選取自訂起始範本的明確定義方案，並釐清支援的設定選項。

由索引模型根據 Issue 內容生成。