[dns-wg] Lower TTLs for NS and DS records in reverse DNS delegations

gregory> Maybe allow users to set TTL on "domain" object in RIPE
gregory> database?

Be nice if we could expand to a more sane/standard set of TTLs for NS/DS
in TLD/SLDs, which makes this non-functional for a slew of such zones.

gregory> Allowed values can be constrained to few common lengths of
gregory> time? The default would be one decided here.

I made this same comment during the recent DNS-OARC. There is value in a
somewhat longer TTL for steady state, to weather temporary glitches in
routing (though current values are way too long for even that). When
doing provider changes and/or KSK rollovers, a shorter value makes more
sense.

I think with some testing and actual data, we can come up with a short
list of useful values without having to allow unconstrained, random
user-picked values that will just create support issues and not really
improve the situation.