改变DoH使用的默认地址（https://example/dns-query)

Have a question or an idea? Please search it [on our forum](https://github.com/AdguardTeam/AdGuardHome/discussions) to make sure it was not yet asked. If you cannot find what you had in mind, please [submit it here](https://github.com/AdguardTeam/AdGuardHome/discussions/new).

### Prerequisites

Please answer the following questions for yourself before submitting an issue. **YOU MAY DELETE THE PREREQUISITES SECTION.**

- [√ ] I am running the latest version
- [√ ] I checked the documentation and found no answer
- [√ ] I checked to make sure that this issue has not already been filed

### Problem Description

如题。DoH默认是dns-query，但是如果部署暴露在公网环境下就比较危险。
As the title shows. DoH request defaults to use "dns-query", but it is dangerous when the host exposed to the public network environment.

### Proposed Solution

改变DoH使用的默认地址（https://example/dns-query)，例如https://example/d，以减少公网部署遭到攻击的风险
Change it, like "https://example/d".

### Alternatives Considered

提供可选择改变DoH使用的默认地址（https://example/dns-query)，例如https://example/d
It can be optional。

### Additional Information

无
None

Thanks.