DNS 64: Synthesize responses for all configured prefixes

### 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

Per documentation:

> dns64_prefixes (since v0.107.23): The list of DNS64 prefixes to use. The first specified prefix will be used to synthesize DNS64 answers. If empty, AdGuard Home will use the default (Well-Known) prefix 64:ff9b::/96.

As a network could have more then one NAT64 gateway, one would like to specifiy more then one prefix and the responses of AdguardHome should contain answers for all prefixes

### Proposed solution

Synthesize AAAA records for all configured prefixes and not only the first one.

### Alternatives considered and additional information

_No response_