Split cache based on ECS

### 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 report a bug and not ask a question

### Operating system type

Linux, Other (please mention the version in the description)

### CPU architecture

AMD64

### Installation

GitHub releases or script from README

### Setup

On one machine

### AdGuard Home version

v0.108.0-a.540+757ddb06

### Description

#### What did you do?

I used an ECS enabled Cloudflare resolver (I use Gateway with no filters on) to allow CDNs to return DNS records more relevant to the locations of clients using my resolver, with the DNS cache enabled to speed up resolution and prevent the need to ask the upstream resolver for the DNS records every time.

#### Expected result

1. Client A who is in the UK always gets UK / EU based IPs delivered by the resolver and cache

2. Client B who is in the US always gets US / CA based IPs delivered by the resolver and cache

#### Actual result

1. If Client A requests the same domain as Client B, and the DNS cache is enabled, if Client A gets answers first, the DNS cache caches the UK / EU IPs and then serves them to Client B instead of asking the resolver again and caching the returned US / CA based ones for Client B.

2. If Client B requests the same domain as Client A, and the DNS cache is enabled, if Client B gets answers first, the DNS cache caches the US / CA IPs and then serves them to Client A instead of asking the resolver again and caching the returned UK / EU based ones for Client A.

#### Screenshots (if applicable)


#### Additional information

Please see the image above for an example of what happens.