[Feature Request] Support AdBlock style syntax as hosts lists in rules

[nvandamme]

Opensnitch is leveraging Hosts format lists, but it incurs many duplicates whenever subdomains are to be blocked as well.

A limited AdBlock style format support could be supported and handle wildcards blocking per domain and subdomains in a compact format without using regexp: https://github.com/AdguardTeam/Adguardhome/wiki/Hosts-Blocklists

# Hosts format
0.0.0.0 example.com
0.0.0.0 test.example.com
...

# AdBlock format
||example.com^

AdGuard Home is actually using this format subset via their own parser library (Go, GPL-3): https://github.com/AdguardTeam/urlfilter