permanent log and data retention

### Prerequisites

- [X] I have checked the [Wiki](https://github.com/AdguardTeam/AdGuardHome/wiki) and [Discussions](https://github.com/AdguardTeam/AdGuardHome/discussions) and found no answer

- [X] I have searched other issues and found no duplicates

- [X] I want to request a feature or enhancement and not ask a question

### The problem

有些时候可能需要永久保留日志和统计数据，但没有这个选项

### Proposed solution

允许永久保留日志及统计数据

### Alternatives considered and additional information

_No response_