$all

### 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

Rules ending with `$all` appear to currently be completely ignored by AdGuard Home. This causes issues with compatibility across lists & content blockers. As an example, if I want to block any domain starting with "test." (and not appearing anywhere else later in the domain or URL), to my understanding, I have to use 2 separate rules for AdGuard Home & uBlock Origin to recognize it:

`||test.*^` (AdGuard Home)

`||test.*^$all` (uBlock Origin)

The problem then is that the rule `||test.*^` is still used by uBlock Origin, and causes severe & undesired breakage across websites, since it appears to work differently there.

(Please correct me if I'm wrong on this & there's a better/more efficient way to do this, new to maintaining filter lists and still learning... But even if I am wrong here, this is only 1 potential example).

### Proposed solution

If rules with $all modifiers were accepted, then this would not be an issue. I could just use:

`||test.*^$all` & it would work on both uBlock Origin & AdGuard Home without issue, as well as other content blockers with a similar logic.

(And again, this is only 1 potential use-case).

I'm also not sure I understand what the downside would be of accepting these rules... the `$all` modifier would mean that the domain is being blocked regardless of context, which is effectively what AdGuard Home is doing at the DNS level, no?

I've just been struggling with this as a list maintainer, as I'd rather avoid having to create a separate list solely for AdGuard Home.

Curious your thoughts on this, and thanks for making this amazing tool :)

### Alternatives considered and additional information

_No response_