DHCP Proxy for unsupported dns servers (EG: Openwrt + odhcpd)

[centerionware]

https://github.com/centerionware/dnsmasq-proxy

I wanted to set up netbootxyz but my openwrt dhcp doesn't support pxe properly. So I took inspiration from samdbmg's version and stripped out just the dhcp proxy part, made an example compose that uses both the official netboot.xyz image and the proxy image. I've tested it on my lan with Proxmox, it doesn't boot as cleanly as I would want but it does seem to boot in the end. Maybe this is normal, i have no idea.

Support was added this January for pxe to odhcpd but afaik hasn't been added to openwrt and I'm running an old version anyway and upgrading would be a long day(s).