resolved: bind .local domains to mDNS with DNS_SCOPE_YES, similar LLMNR

resolved: bind .local domains to mDNS with DNS_SCOPE_YES, similar LLMNR

Previously, we'd return DNS_SCOPE_MAYBE for all domain lookups matching
LLMNR or mDNS. Let's upgrade this to DNS_SCOPE_YES, to make the binding
stronger.

The effect of this is that even if "local" is defined as routing domain
on some iface, we'll still lookup domains in local via mDNS — if mDNS is
turned on. This should not be limiting, as people who don't want such
lookups should turn off mDNS altogether, as it is useless if nothing is
routed to it.

This also has the nice benefit that mDNS/LLMR continue to work if people
use "~." as routing domain on some interface.

Similar for LLMNR and single label names.

Similar also for the link local IPv4 and IPv6 reverse lookups.

Fixes: #10125