libknot: merge RCODE name sets

src/knot/nameserver/process_query.c

src/libknot/codes.c

src/libknot/codes.h

src/libknot/consts.h

src/libknot/rrtype/tsig.c

src/libknot/tsig-op.c

src/libknot/tsig-op.h

src/utils/common/sign.c