Idea: Print (configurable) list of omitted fields/items

Picking up the example from README, we could add some infos on what was skipped:

spec:
   # 2 fields omitted (volumes, gracefulShutdownTimeout)
   containers:
     # 1 item ommited (my-sidecar)
     - name: app
       # 2 items omitted (volumeMounts, imagePullPolicy)
       env:
         - name: LOG_LEVEL
-          value: debug
+          value: info
-      image: "myapp:2.0"
+      image: "myapp:1.0"

We don't want to print an unlimited long list of fields/items, so cap it to e.g. 3 list items (configurable, e.g. 0 turns them off entirely) like that:

# 20 items omitted (volumeMounts, imagePullPolicy, foo, ...)

Fields are just the field names, so that should easily be convertable to a String.
Items are a bit harder, I guess that only works when a ArrayMatchMode is set up? But didn't even use the crate yet, so not sure.

Start with the README example and trace the entry point for ArrayMatchMode to understand how omitted fields and items are identified. Define how the configurable list cap, including 0 to disable it, should apply to both kinds of omissions. Done means the diff can report capped field and item names without producing an unlimited list.