Add a script to copy the content of the custom folder to a running pod

For now it is only labels, but adding anything supported will work
(robots.txt, public files, templates, etc)

The content will be copied to the /data/gitea/ folder that is a mounted
persistent volume

https://docs.gitea.io/en-us/customizing-gitea/

script/copy_customization

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+
+for podname in $(kubectl get pods -l name=gitea-server -o json \
+  | jq -r '.items[].metadata.name'); do
+    for path in ./kubernetes/custom/*; do
+      echo "Copying ${path}..."
+      kubectl cp "${path}" "${podname}":"/data/gitea/"
+    done
+  # Fix permissions
+  kubectl exec "${podname}" -- chown -R 1000:1000 /data/gitea/
+  done