Add ip_classify custom function

[gdollasigns]

Summary

Adds a new ip_classify custom function that supersedes the approach in #185.

Key improvements over #185

• Uses Python's ipaddress module — stdlib, battle-tested, no manual string parsing
• Covers 15 RFC-defined ranges vs 3 in added: function to sort public and private IPv4 #185 — adds loopback, link-local, CGNAT (RFC6598), documentation (RFC5737), multicast, reserved, broadcast, and more
• Correct loopback handling — 127.x.x.x correctly classified as private (was a bug in added: function to sort public and private IPv4 #185)
• Invalid IPs surfaced — returned as classification: 'invalid' with a reason, rather than silently dropped
• List output — one entry per IP with ip, classification, and reason fields, making it easy to filter in playbooks (e.g. classification == 'public')
• snake_case naming — consistent with repo convention
• Targets 8.6, Python 3.13 — up to date with current platform

Outputs

Each IP in the input list produces one output record:

Field	Description
ip (CEF type: ip)	The IPv4 address
classification	public, private, or invalid
reason	e.g. Private (RFC1918), Loopback (RFC1122), Public, Not a valid IPv4 address

Test coverage

Validated against:

• RFC1918 private ranges (10.x, 172.16-31.x, 192.168.x)
• Loopback (127.0.0.1)
• Link-local (169.254.x.x)
• CGNAT (100.64.x.x)
• Documentation ranges (192.0.2.x, 198.51.100.x, 203.0.113.x)
• Public IPs (8.8.8.8, 1.1.1.1, 208.67.222.222)
• Invalid inputs (256.0.0.1, not-an-ip)

Closes #185