Global rules, which apply to all created servers (all devices)

### Issue Details

I find myself duplicating many rules or filters across multiple servers on AGDNS, which overtime becomes cumbersome to manage, checking what has been added and what hasn't.

### Proposed solution

I feel this could be better handled by globally applied settings for filters, rules, etc.
A similar feature exists in AdGuard Home under the New Client settings, which I feel could be of use in AdGuard DNS.


If I was designing it, I'd probably create a "Global" server, under server settings - or somewhere close-by with a similar layout to the servers, which makes it familiar.

### Alternative solution

_No response_