Favorite files and folders

### Please agree to the following

- [X] I have searched [existing issues](https://github.com/cryptomator/android/issues?q=) for duplicates
- [X] I agree to follow this project's [Code of Conduct](https://github.com/cryptomator/android/blob/develop/.github/CODE_OF_CONDUCT.md)

### Summary

Favorite files and folders

### Motivation

Star files and folders as favorite to quickly access them without the need to navigate between directories.

### Considered Alternatives

_No response_

### Anything else?

_No response_

该 issue 未指定任何文件、测试或入口点。首先梳理 Android 应用中如何显示和浏览文件与文件夹，然后在实现之前定义收藏夹所需的存储、显示和访问行为；当无需浏览目录即可访问加星标的文件和文件夹时，即表示完成。

由索引模型根据 Issue 内容生成。