Issue-758: Revise and update Kryo serialization mechanism

- update of the Kryo library to the latest version
- use an external library to get common serializers (for immutable collections)
- simplify the encoding process (no more multiple attempts)

Tested on a basic flow: login for a service, ST validation, logout
I tend to think it's better to keep the current order and add the missing serializers at the end, to allow CAS deployers to upgrade without loosing the current serialized tickets. If it's really possible...