use pure nix for manifests, yaml is too buggy

kubernetes/kubernetes.nix

@@ -1,6 +1,7 @@
 {
   imports = [
     ./charts
+    ./manifests
   ];
 
   networking.firewall.allowedTCPPorts = [6443];
@@ -8,8 +9,5 @@
   services.k3s = {
     enable = true;
     role = "server";
-    manifests = {
-      test-color.source = ./manifests/test;
-    };
   };
 }