Merge branch 'conf-cache-optimization' into 'master'

src/knot/conf/base.c

src/knot/conf/base.h

src/knot/modules/dnsproxy.c

src/knot/nameserver/process_query.c

src/knot/nameserver/update.c

src/knot/query/query.c

src/knot/server/tcp-handler.c

tests/confio.c