add opensearch addons

opensearch-master/rootfs/etc/cont-init.d/10-copy-config

@@ -0,0 +1,14 @@
+#!/command/with-contenv bash
+set -euo pipefail
+SRC_DIR=/rootfs-config
+DST_DIR=/usr/share/opensearch/config
+if [ -d "$SRC_DIR" ]; then
+  echo "[cont-init] Copying config snippets from $SRC_DIR to $DST_DIR"
+  for f in "$SRC_DIR"/*; do
+    base=$(basename "$f")
+    if [ ! -f "$DST_DIR/$base" ]; then
+      cp "$f" "$DST_DIR/"
+      echo "[cont-init] Copied $base"
+    fi
+  done
+fi