chore(kontemplate): Prepare kontemplate for depot-merge

This merge will not yet include moving over to buildGo.nix, as support
for testing and such is not present in that library yet.

ops/kontemplate/context/testdata/explicit-subresource-path.yaml

@@ -0,0 +1,8 @@
+---
+context: k8s.prod.mydomain.com
+include:
+  - name: parent
+    path: parent-path
+    include:
+      - name: child
+        path: child-path