Integrating Tools from other frameworks into CaptainAgent

[LeoLjl]

This PR integrates tools from other platforms into CaptainAgent. This is achieved through interoperability. For developers, they need to modify only one line for defining CaptainAgent instance. For example:

# assume that ag2_tool is a Tool instance
captain_agent = CaptainAgent(
    name="captain_agent",
    llm_config=llm_config,
    code_execution_config={"use_docker": False, "work_dir": "groupchat"},
    agent_lib="captainagent_expert_library.json",
    tool_lib=[ag2_tool],  # The main difference lies here: we pass the converted tool to the agent
    agent_config_save_path=None,
)

The only difference is to pass a list of AG2 Tools into tool_lib, this will let equip all the agents created within nested chat with the AG2 tools, and they can use python code to call the relevant tools without the need to defining it in the code.

Why are these changes needed?

Related issue number

This PR closes #307

Checks

• I've included any doc changes needed for https://docs.ag2.ai/. See https://docs.ag2.ai/docs/contributor-guide/documentation to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[skzhang1]

LGTM