Add support for CIDR collapsing in excluded_prefixes

[d-uzlov]

Overview

When running tests I noticed that excluded_prefixes list is unnecessary long.

There are a lot of /32 entries which could be covered by parent entries which are also included.

{
    "excluded_prefixes": [
        "10.100.0.1/32",
        "10.100.0.10/32",
        "10.100.34.238/32",
        "10.100.41.79/32",
        "10.100.52.128/32",
        "10.100.126.150/32",
        "10.100.136.187/32",
        "10.100.167.242/32",
        "10.100.223.27/32",
        "10.96.0.0/12",
        "192.168.0.0/16"
    ]
}

Here 10.96.0.0/12 specifies range 10.96.0.0 - 10.111.255.255, which includes all the 10.100.x.x entries.
It may be useful to add some mechanism to skip smaller prefixes that are covered by larger ones.