hippo-cms-l10n scanner incorrectly ignores some Java resource bundles (.properties) without corresponding .class file

As discovered through CMS-10082 the current way Java resouce bundles are detected, requiring a corresponding .class file in the same folder, is not covering all use-cases.

As a first step I've added warn logging for such skipped .properties resources so its clear which and where these use-cases occur.

As .properties files can be used for other purposes than localization we need an automated solution to:

• detect such 'unknown' resource bundle resources and fail the report goal
• support custom (maven plugin) configuration per localization module to explicitly include/exclude such resource bundle resources (kind of similar to maven rat plugin)