Find hosts across registered networks using CIDR

[pederhan]

network list_used_addresses only supports listing hosts from a single network.

host find does not support specifying a network or using CIDR at all.

It would be useful to support searching for hosts from a given range of networks, i.e.:

host find -network 172.16.0.0/19
# And/or
network list_used_addresses 172.16.0.0/19

network list_used_addresses

If we go with this command, we need to change the way we perform network lookups, because currently we use /network/<network> to perform these lookups, which does not work for ranges.

host find

Need to investigate if we can search for networks on the /hosts/ endpoint.