hipp-cms-l10n:extract generated invalid hippoecm-extension.xml for repository resource bundles in sub folders

The extract goal somehow generates a hippoecm-extension.xml with initialize item node names derived from the repository resource bundle file (.json), e.g. for file /bar.json node names like "<module-name>-bar-translations_<locale>"
However, if that file is located in a sub folder, e.g. /foo/bar.json it will generate an illegal node name like "<module-name>-foo/bar-translations_<locale>".