servo: lay the skeleton files for a XMPP (jabber) server

machines/servo/services/default.nix

@@ -2,6 +2,7 @@
 {
   imports = [
     ./ddns-he.nix
+    ./ejabberd.nix
     ./freshrss.nix
     ./gitea.nix
     ./goaccess.nix

machines/servo/services/ejabberd.nix

@@ -0,0 +1,13 @@
+# docs:
+# - <https://docs.ejabberd.im/admin/configuration/basic>
+{ lib, ... }:
+
+# TODO: enable
+lib.mkIf false {
+  sane.impermanence.service-dirs = [
+    { user = "ejabberd"; group = "ejabberd"; directory = "/var/lib/ejabberd"; }
+  ];
+  # TODO: allocate UIDs/GIDs ?
+  services.ejabberd.enable = true;
+  services.ejabberd.configFile = ./ejabberd.yaml;
+}