refactor: move modules to common folder since separation was unsound

modules/meta.nix

@@ -0,0 +1,27 @@
+{
+  config,
+  lib,
+  ...
+}: let
+  inherit
+    (lib)
+    mkOption
+    types
+    ;
+in {
+  options.node = {
+    name = mkOption {
+      description = "A unique name for this node (host) in the repository. Defines the default hostname, but this can be overwritten.";
+      type = types.str;
+    };
+
+    secretsDir = mkOption {
+      description = "Path to the secrets directory for this node.";
+      type = types.path;
+    };
+  };
+
+  config = {
+    networking.hostName = config.node.name;
+  };
+}