renumber: get rid of netmask limitation, now support any netmask

[cronfy]

Remove limitation of using /8 /16 and /24 netmasks only for renumbering.

Now any kind of netmask is allowed, for example:

    modules = {
        renumber = {
            -- Remap /26 subnet (64 ip addresses)
                        -- 166.55.77.128 -> 127.0.0.192
                        -- 166.55.77.129 -> 127.0.0.193
                        -- ...
            {'166.55.77.128/26', '127.0.0.192'},
        }
    }

[vcunat]

Uh, is the renumber module getting so popular now?

Migrated to https://gitlab.nic.cz/knot/knot-resolver/-/merge_requests/1306

[ValdikSS]

Uh, is the renumber module getting so popular now?

There's ongoing "Internet without Borders" hackathon with tasks to improve the connectivity using DNS resolver hacks: https://internetborders.net/goodbye-dpi/ As I mainly use knot-resolver, I encourage people to improve it in the first place.

[vcunat]

FYI if you're using this code already, the masking was incorrect: https://gitlab.nic.cz/knot/knot-resolver/-/merge_requests/1306#note_254590