Validator component fails on XSD with indirect relative import

When using the validator component with an XSD that references a second XSD on a different path, and where the second XSD references a third XSD using a relative path, the path of the third XSD is resolved relative to the first schema rather than relative to the second. This looks similar to CAMEL-5321, but the schemas that trigger this issue necessarily involve an additional layer of includes.

I will include a test case that I rolled into the tarball from CAMEL-5321.