Add botnet-filter by malware-filter

### Prerequisites

- [x] The blocklist is created specifically for DNS-level blockers;
- [x] The blocklist is regularly updated (at least 10 updates per month);
- [x] The blocklist is known and popular;
- [x] The blocklist satisfies [the repo requirements](https://github.com/AdguardTeam/HostlistsRegistry#-what-blocklists-can-be-added-here);

### Blocklist name

Botnet IP Blocklist

### Blocklist category

Malware&phishing blocking

### Homepage

https://gitlab.com/malware-filter/botnet-filter

### Explanation

The botnet-filter is part of the malware-filter set of lists of which phishing-filter and urlhaus-filter are already featured in the AdGuard DNS dashboard selectables. By adding the AdGuard Home compatible botnet-filter, the malware-filter options would be complete. Their reputation is very respectable.