Support renaming of asset file

### Feature request

It would be nice have an option to rename an asset in certain situations, e.g. when having conflicts in third party stuff.
Add property "filename" with the new file name.
Will only be used when the glob resolves to exactly one file.
```
"assets": [
{ "glob": "**/*", "input": "./assets/", "output": "./assets/" },
{ "glob": "favicon.ico", "input": "./", "output": "./", "filename": "newname.ico" },
]
```

首先跟踪解析并复制 assets glob 的 Angular CLI 代码，将此 issue 中的配置示例作为预期输入。找到相关的 asset 处理测试，然后验证单个匹配的 asset 可以使用配置的文件名，同时现有的 glob 行为保持不变。

由索引模型根据 Issue 内容生成。