before root hints were hardcoded to the resolver,
now they are present in form of a cut in the resolution
context, and the modules can add/remove/replace them
on the fly

the Redis backend supports UNIX, TCP and custom ports
no real transactions nor iteration, but it’s not needed at the moment
transactions keep replies in a freelist, which is purged on transaction
commit / abort

fixes potential cache key oob write

this relies on a lot of things (intrinsic), frame pointer and symbol dynamic symbol table

also some cleanup and version bump to Q2

previously a CNAME RR could be merged as a queried type RR, leading to failed cache lookups as ‘expired’