Refactor CAS internals support (CAS + Kryo Serialization)

Question

https://docs.google.com/document/d/1k-Cw8QiRHVA91nI-rww4Bh1ealU-qa0avBmUbDCofqQ/edit#heading=h.8r6u5pmj351p

该提问来源于开源项目：pac4j/pac4j

Answer 1

This is a huge change I'd prefer not to tackle in one PR. So I plan:

1) Add a mechanism to handle attributes serialization into strings (to be enabled by CAS) 2) Remove Kryo thanks to 1) (pac4j does not need it, in fact, just CAS does) 3) Refactor converters & profile definitions 4) Clean unit tests on specific objects (FacebookPhoto) and re-run all manual tests