[Feature] 从数据库备份文件还原/恢复数据

[WindDrift]

Checklist

• I have already read docs/Tips.md, but my feature is not implemented.
• My suggested feature was not mentioned by others, and it is not a duplicate feature.

Summary

支持从指定备份文件还原/恢复数据，以便设备迁移数据与应对遇到致命问题的降级还原。

Solution or Design

可以在【应用设置】——【文件管理】——【数据文件夹】中新增一个【恢复数据库】的选项，然后根据指引选择指定数据库备份文件并开始恢复数据库。