The xva builder isn't working

[4censord]

The xva builder is currently not tested and doesn't seem to work
packer currently doesn't recognize xenserver-xva as a valid source
this can be seen with the minimal configuration

source "xenserver-xva" "cloudinit-base" {
}
build {
  sources = ["sources.xenserver-xva.cloudinit-base"]
}

packer validate currently errors with
Error: Unknown source type xenserver-xva

I assume it would need to be declared in packer.json?

• get packer to recognize xenserver-xva
• get an example working
• check and/or write tests
• document the xva builder