option like ipset but execute external command

### 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

### Description

completely understand that maybe that feature not very popular.. for some reason, my adguardhome instance and router (which using ipset list) is different devices. so using ipset (or ipset_file) are not works for me in that case

option to call external script/program/http request on every new ip address resolved for specified domains will be great _(so it will be possible on router side to add it into ipset somehow, not a problem)_

as alternative is take output of ipset list and somehow sync it with router with cron...
____
or
_as another way (and maybe preferred one, instead of adding completely new functionality that may be useful for couple of users) is iplist available throught api so if someone need it, can get it with simple http call