Integrate AgentOptimizer (microsoft#1767)

* draft agent optimizer

* refactor

* remove

* change openai config interface

* notebook

* update blog

* add test

* clean up

* redir

* update

* update interface

* change model name

* move to contrib

* Update autogen/agentchat/contrib/agent_optimizer.py

Co-authored-by: Jack Gerrits <[email protected]>

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Co-authored-by: “skzhang1” <“[email protected]”>
Co-authored-by: Beibin Li <[email protected]>
Co-authored-by: Jieyu Zhang <[email protected]>
Co-authored-by: Jack Gerrits <[email protected]>