Refactoring test metadata server.
- Refactoring to enable federation metadata to include existing metadata.
Refactored IdentityProvider Active idp list handling.
- Introduced a new ActiveIdentityProvidersMap class to be used instead of exposing a dictionary. The new class
  can provide some intelligent aggregation from configured idps and federations.
Federation metadata loading.
- Changed config file structure to include federations.
- Loads and uses idps from federation.