GH-113171: Fix "private" (non-global) IP address ranges (GH-113179)

* GH-113171: Fix "private" (really non-global) IP address ranges

The _private_networks variables, used by various is_private
implementations, were missing some ranges and at the same time had
overly strict ranges (where there are more specific ranges considered
globally reachable by the IANA registries).

This patch updates the ranges with what was missing or otherwise
incorrect.

I left 100.64.0.0/10 alone, for now, as it's been made special in [1]
and I'm not sure if we want to undo that as I don't quite understand the
motivation behind it.

The _address_exclude_many() call returns 8 networks for IPv4, 121
networks for IPv6.

[1] https://github.com/python/cpython/issues/61602