feat(module:segmented): redesign the segmented component

[HyperLife1119]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/NG-ZORRO/ng-zorro-antd/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• Application (the showcase website) / infrastructure changes
• Other... Please describe:

What is the current behavior?

Issue Number: N/A

1. ngModel 的值是 index
2. 自定义渲染用法不符合人体工学

<nz-segmented [nzLabelTemplate]="templateRef" [nzOptions]="options"></nz-segmented>
<ng-template #temp let-index="index">
  @switch (index) {
    @case (0) {
      <nz-avatar nzSrc="https://joeschmoe.io/api/v1/random"></nz-avatar>
      <div>User 1</div>
    }
    @case (1) {
      <nz-avatar nzText="K"></nz-avatar>
      <div>User 2</div>
    }
    @case (2) {
      <nz-avatar nzIcon="user"></nz-avatar>
      <div>User 3</div>
    }
  }
</ng-template>

What is the new behavior?

1. 将 ngModel 的值改为 option.value
2. 新增 [nz-segmented-item] 组件，提供直接的自定义渲染功能

<nz-segmented>
  <label nz-segmented-item nzValue="user1">
    <div [style.padding.px]="4">
      <nz-avatar nzSrc="https://joeschmoe.io/api/v1/random" />
      <div>User 1</div>
    </div>
  </label>
  <label nz-segmented-item nzValue="user2">
    <div [style.padding.px]="4">
      <nz-avatar nzText="K" [style.background]="'#f56a00'" />
      <div>User 2</div>
    </div>
  </label>
  <label nz-segmented-item nzValue="user3">
    <div [style.padding.px]="4">
      <nz-avatar nzIcon="user" [style.background]="'#87d068'" />
      <div>User 3</div>
    </div>
  </label>
</nz-segmented>

Does this PR introduce a breaking change?

• Yes
• No

1. ngModel 的值从 index 修正为 option.value
2. 不再需要 nzLabelTemplate input，将其移除
3. nzValueChange 的类型从 EventEmitter<number> 修改为 EventEmitter<number | string>

Other information