Restrict hosting of public dns resolver

### 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

Many issues and discussion are about hosting a public dns resolver which is in general not a good idea.

### Proposed solution

Adguard Home should restrict the hosting of public DNS servers or at least warn the user about possible consequences.

### Alternatives considered and additional information

_No response_