sci-misc/llama-swap: add llama-swap-223 vendored sources

Upstream source tarball plus pre-vendored Go modules (go mod vendor
against go.sum from upstream's v223 tag). Lets sci-misc/llama-swap
in the stuff overlay build with network-sandbox enabled.

Generated via:
  curl -L https://github.com/mostlygeek/llama-swap/archive/refs/tags/v223.tar.gz | tar -xz
  cd llama-swap-223 && go mod vendor
  tar --owner=0 --group=0 --sort=name -cJf llama-swap-223.tar.xz llama-swap-223

Author: istitov