Refactor:

- Support for module features
- Remove kubenix.module and rather use explicit modules
- Make tests framework independent of k8s module
- Remove metacontroller submodule, which will go to kubenix-modules
- Improved submodule propagation and passthru
- Added additional test for k8s-submodule

modules/submodule.nix

@@ -0,0 +1,40 @@
+{ config, lib, ... }:
+
+with lib;
+
+{
+  imports = [ ./base.nix ];
+
+  options.submodule = {
+    name = mkOption {
+      description = "Module name";
+      type = types.str;
+    };
+
+    description = mkOption {
+      description = "Module description";
+      type = types.str;
+      default = "";
+    };
+
+    version = mkOption {
+      description = "Module version";
+      type = types.str;
+      default = "1.0.0";
+    };
+
+    tags = mkOption {
+      description = "List of submodule tags";
+      type = types.listOf types.str;
+      default = [];
+    };
+
+    passthru = mkOption {
+      description = "Attribute set to passthru to parent";
+      default = {};
+      type = types.attrs;
+    };
+  };
+
+  config._module.features = ["submodule"];
+}