ch-proxy: add meta, set mainProgram

pkgs/ch-proxy/package.nix

@@ -23,4 +23,16 @@ stdenv.mkDerivation {
       ];
       root = ./.;
     };
+
+  meta = {
+    mainProgram = "ch-proxy";
+    license = [ lib.licenses.gpl3 ];
+    homepage = "https://forge.someonex.net/else/uvms/src/branch/master/pkgs/ch-proxy";
+    description = ''
+      An FD-passing proxy for cloud-hypervisor (firecracker, crosvm),
+      compatible, as a ProxyCommand, with ssh. This only really exists
+      because https://github.com/systemd/systemd/blob/cb19dbb97f062a09a61a0be5f7ebf1e4cda7fb78/src/ssh-generator/ssh-proxy.c
+      was not yet merged into Nixpkgs at the time.
+    '';
+  };
 }