daemon/lua: bindings for packet sections and data

example:
local rr = pkt:section(kres.section.ANSWER)
for i = 1, #rr do
	if rr[i].type == kres.type.A then
		print(kres.dname2str(rr[i].owner))
		print(‘rdlen:’, #rr[i].rdata)
	end
end