[high] Add dynamic-dns warninglist generator

[elhoim]

BLUF

• What: automates lists/dynamic-dns, last refreshed 2023-11-30, from the upstream it was originally hand-copied from.
• Source: alexandrosmagos/dyn-dns-list (links.txt) — maintained and auto-refreshed.
• Evidence it is the right source: 29,200 of the 35,467 committed entries appear in it verbatim.
• Effect: +10,069 domains (35,467 → 45,536), 0 removed.
• Priority: high — the list is ~21 months stale and missing about a fifth of the provider space it is meant to cover.

Detail

Unions, never replaces. Every entry committed today survives untouched. Upstream feeds track only what is live now, so a naive regeneration would silently drop still-useful entries; nothing is ever removed automatically.

6,267 committed entries are not in the upstream feed today — providers that shut down, and entries MISP maintainers added by hand. A dynamic DNS domain that stopped being offered last year still explains an indicator seen last year, so removal stays a human decision.

The leading-dot entry convention (.duckdns.org) is preserved exactly; it is what makes evil.duckdns.org match, and changing it would silently alter matching on every deployed instance. name, description, type and matching_attributes are unchanged.

Refuses to write an empty list. Idempotent — a second run logs No changes … skipping version bump. Python 3.8-compatible.