Support for CIDR subnets in no_proxy/NO_PROXY

This enables matching numeric hosts against CIDR style subnet
matches in no_proxy environment variable.

Based on work by Thermi.

Co-authored-by: Noel Kuntze <noel.kuntze@thermi.consulting>
3 jobs for tt-subnet-match in 48 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Test
passed #291917
docker-alpine x86_64
test-meson:alpine

00:00:25

passed #291916
docker-alpine x86_64
test:alpine

00:00:25

passed #291918
docker-alpine x86_64
test:debian

00:00:47