建议Modal对话的取消、确定按钮可以不显示或者增加Window对话框组建

### iView 版本号
0.9.10

### 操作系统/浏览器 版本号
Windows7/Chrome 54

### Vue 版本号
1.0.21

### 问题现象，以及你期望的结果是怎样的?
1. 现在的Modal组建不能控制取消、确定按钮是否显示
2. 或者建议新增Window组建：可以最大化、最小化、拖拽、拉伸等

No file or test is named. Start by locating the existing Modal component and reviewing its current cancel and confirm button behavior. Before implementation, clarify whether button visibility or a separate Window component is intended, then define acceptance criteria for the selected scope.

Written by the indexing model from the issue text.