RTE Backend Cache

I always run in caching issues on configuring the rte stylesheet. I would suggest to add a version string.

https://github.com/sebkln/basetemplate10/blob/master/Configuration/RTE/Custom.yaml#L15

```
    contentsCss:
      - "EXT:rte_ckeditor/Resources/Public/Css/contents.css"
      - "EXT:sitepackage/Resources/Public/Css/rte_ckeditor.css?v1.00"
```