Adding test with SAmbi's metadata.
- Want to make sure that AuthServices can read and works with some real world metadata.
- Refactored Federation class to allow direct injection of metadata without downloading.
- Refactored out Federation class' dependency on the configuration.
- Added an filtering XmlReader to work around MetadataSerializers' lackings upport of the used XML canonicalization transform.
Added filtering of keys based on use
- We're not interested in encryption keys for the moment.
Testing with real world metadata
- Updated key extraction to only take the key with the right type.