move authelia into separate file

hosts/rpi4/authelia.nix

@@ -0,0 +1,22 @@
+{ config, lib, pkgs, ... }:
+{
+  # authelia
+  options.services.nginx = let
+    inherit (lib) types;
+    mkAttrsOfSubmoduleOpt = module: lib.mkOption { type = with types; attrsOf (submodule module); };
+
+    # make system config accessible from submodules
+    systemConfig = config;
+
+    # submodule definitions
+    locationModule' = vhostAttrs: { name, config, ... }: {
+    };
+    vhostModule = { name, config, ... }@attrs: {
+      options.locations = mkAttrsOfSubmoduleOpt (locationModule' attrs);
+    };
+
+  in {
+    virtualHosts = mkAttrsOfSubmoduleOpt vhostModule;
+  };
+
+}

hosts/rpi4/services.nix

@@ -2,6 +2,7 @@
 {
   imports = [
     ./gitea.nix
+    ./authelia.nix
   ];
   config = {