IP blocklists/allowlists and domain blocklists in DNS access settings

### Prerequisites

- [x] I am running the latest version (v0.98.1)
- [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
In *DNS Settings* → *Disallowed Clients*, it may feel a bit inconvenient to have to add IP addresses one at a time manually. Could it be a possibility to make it possible to use IP blacklists (e.g. [FireHOL Level 1](https://raw.githubusercontent.com/firehol/blocklist-ipsets/master/firehol_level1.netset)) to keep the list of disallowed clients updated and large?

Note that this is **not** to be confused with the theorethical use of IP blacklists as filterlists to block web connections.

### Proposed Solution
Add a setting/menu dedicated to IP blacklists, which are then used to disallow DNS requests from those IPs. They should also be updated in much the same way as adblock/domain/hosts filterlists are, although not as often; and the use of multiple IP blacklists should also be permitted.

### Alternatives Considered
Expanding on the *Disallowed Clients* or *Filters* settings to allow pasting IP blacklist URLs into them, is also a possibility.

### Additional Information
I'll confess that this is a part of how I use my AdGuard Home as a straightforward unencrypted public DNS server (although I intend to be the only user of it) by opening port 53 to it, and that I was hoping to be able to use IP blocklists, as a preferable alternative to setting up an entire firewall program and undoubtedly struggling with it. More details about my intentions are at https://hub.filterlists.com/t/remote-access-to-agh-pi-hole-dns-servers-the-do-s-and-dont-s/57