Hope to add keyword-matching domain name functionality

### 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

When using AdGuardHome for domain allocation to different servers, I use Clash rules and convert them into AdGuardHome rules via a shell script. However, a small portion of the Clash rules includes keyword types, which are not supported by AdGuardHome, leading to incorrect matching for these keywords. For example, "DOMAIN-KEYWORD, aliyun" cannot be matched in AdGuardHome. The script appending ".com" at the end can only match "aliyun.com," but domains like "data.aliyundrive.net" and "arms-retcode.aliyuncs.com" are incorrectly allocated to the wrong DNS server. Therefore, it would be helpful to add support for keyword matching, such as using "[/aliyun/]$dns_servers" for keyword matching.

### Proposed solution

Keyword Matching

### Alternatives considered and additional information

When keywords can be matched for "[$dns_servers"]"