Document the option to detect RPI4 platform in dhcp conf exemple

[nodje]

The idea would be to document how to detect RPi4 platform in DHCP. If at all possible.
I guess it would be already documented if it was, but otherwise would be good to understand why it's not possible.

It would sit in this section
https://netboot.xyz/docs/docker#examples

option arch code 93 = unsigned integer 16;

subnet 192.168.0.0 netmask 255.255.255.0 {
  range 192.168.0.34 192.168.0.254;       # Change this range as appropriate for your network
  next-server 192.168.0.33;               # Change this to the address of your DHCP server
  option subnet-mask 255.255.255.0;
  option routers 192.168.0.1;             # Change this to the address of your router
  option broadcast-address 192.168.0.255;
  option domain-name "mynetwork.lan";     # This is optional
  option domain-name-servers 1.1.1.1;
  if exists user-class and ( option user-class = "iPXE" ) {
    filename "http://boot.netboot.xyz/menu.ipxe";
  } elsif option arch = encode-int ( 16, 16 ) {
    filename "http://boot.netboot.xyz/ipxe/netboot.xyz.efi";
    option vendor-class-identifier "HTTPClient";
  } elsif option arch = 00:07 {
    filename "netboot.xyz.efi";
  } else {
    filename "netboot.xyz.kpxe";
  }
}

this should include an option to assign netboot.xyz-rpi4-snp.efi if some detection is possible.