chore: switch storagesvc to S3 backend (ngcloud msk-1)

- helm/fission-values.yaml: storageType=s3, bucket=sless-functions, endPoint=https://s3.msk-1.ngcloud.ru
- helm/fission-values-pv.yaml: сохранён PV конфиг для быстрого возврата
- helm/fission-s3-secret.yaml: credentials (в .gitignore, не в репо)
- .gitignore: добавлен helm/fission-s3-secret.yaml

Возврат на PV: kubectl delete deploy executor router storagesvc -n fission
  helm upgrade fission ... -f helm/fission-values-pv.yaml --no-hooks

.gitignore

@@ -19,6 +19,7 @@ console/fission-console
 
 # Secrets / tokens
 token.txt
+helm/fission-s3-secret.yaml
 
 # Test logs
 test-results/