when a NS is in the TIMEOUT, it can’t be autoselected by default but only probed after a successful dice roll - however in some scenarios we’d like to probe timeouting servers more thoroughly 

simplified bee foraging strategy, by default each query goes to the most rewarding NS
however with a chance proportional to the NS RTT, a server may be probed even if it isn’t the most rewarding

prevents pointless caching of TTL={0,1} records

previously the NS address list was wiped out, this prevents them from being added in the first place

some servers break qname m12n by sending REFUSED, this accepts such answer and requeries with m12n turned off 

score has now meaning of ‘RTT’, maximum RTT is 10s
which is also the penalty for timeout
unknown servers are favorized as 10ms servers to
encourage resolver to try them out, if they contain
unknown glue they are most favourable

Merge branch 'cache-api-noglobal-wip' of gitlab.labs.nic.cz:knot/resolver into cache-api-noglobal-wip

the only condition of caching an answer is that it resolves a query and is not already cached
(ok, it must be negative at this point…)

if an authoritative answer comes and the server responds correctly, but appends out-of-bailiwick NS records, ignore them but resolve the query

previously it restarted query production for each NS, now it loops until it finds a suitor or bails out

this fixes a bug when storing NODATA without SOA,NS or any other ‘authoritative answer’ hint

since the zone cut is looked up after layers now, it
is pointless to search for minimized names from cache,
since this is the same operation as searching for a zone cut

if the query is satisfied from cache, it doesn’t need a zone cut lookup, so it may be deferred until an outbound query is about the be issued.