Moving Baloo and Baloo-widgets into KDE SC

[David Edmundson]

This doesn't need to be be in the first release but I would like an
exposed Qt interface to fsetxattrs and xgetxattrs.

Ideally this would be exposed in the File object, maybe with some sort
of QVariantMap userProperties() method.

FileFetchJob would then load all the properties in the same way
ratings/comments/tags are now. Ratings etc. become just specially
named entries in this map with convenience methods to get/set them.

This is really needed in order to complete the porting of kdenlives
usage where we are tagging custom attributes (license type + creator)