Update speaker selector in GroupChat and update some notebooks (#688)

* Add speaker selection methods

* Update groupchat RAG

* Update seed to cache_seed

* Update RetrieveChat notebook

* Update parameter name

* Add test

* Add more tests

* Add mock to test

* Add mock to test

* Fix typo speaking

* Add gracefully exit manual input

* Update round_robin docstring

* Add method checking

* Remove participant roles

* Fix versions in notebooks

* Minimize installation overhead

* Fix missing lower()

* Add comments for try_count 3

* Update warning for n_agents < 3

* Update warning for n_agents < 3

* Add test_n_agents_less_than_3

* Add a function for manual select

* Update version in notebooks

* Fixed bugs that allow speakers to go twice in a row even when allow_repeat_speaker = False

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Co-authored-by: Adam Fourney <adamfo@microsoft.com>