[Feature Request] Add Proxy Protocol Support

### Prerequisites

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

### Problem Description
When running AdGuard Home behind dnsdist, AGH will see dnsdist's IP as the source IP, now that dnsdist is supporting Proxy Protocol, it would be good if AGH have the capability to parse the proxy protocol

### Proposed Solution
Add the ability to parse Proxy Protocol

### Alternatives Considered
Use EDNS as client's source IP in statistics https://github.com/AdguardTeam/AdGuardHome/issues/1727

### Additional Information

* https://dnsdist.org/advanced/passing-source-address.html#proxy-protocol
* https://github.com/pires/go-proxyproto