add the missing config/cfgroot/xdpdns-settings file
and use ENABLE_DNSBLOCK=on by default, so XDP DNS
Blocklist is enabled by default.
also add domainfile so when BPFire reboot first time
and when xdpdns init startup, it will not complain
missing domainfile
Signed-off-by: Vincent Li <vincent.mc.li@gmail.com>
