feat!: Add support for model family specification #2895

Job	Run time
docs (./packages/autogen-core)	1m 33s
format	58s
lint	57s
mypy (./packages/autogen-core)	2m 15s
test (./packages/autogen-core)	52s
mypy (./packages/autogen-magentic-one)	1m 17s
pyright (./packages/autogen-core)	1m 7s
test (./packages/autogen-magentic-one)	1m 32s
mypy (./packages/agbench)	1m 4s
pyright (./packages/autogen-magentic-one)	1m 1s
test (./packages/autogen-ext)	3m 1s
mypy (./packages/autogen-ext)	1m 57s
pyright (./packages/agbench)	1m 2s
test (./packages/autogen-agentchat)	54s
mypy (./packages/autogen-agentchat)	1m 46s
pyright (./packages/autogen-ext)	1m 10s
pyright (./packages/autogen-agentchat)	1m 4s
check-proto-changes-python	1m 8s
docs-example-check (./packages/autogen-core)	2m 28s
	27m 6s

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