Activate deactivate agents

[peterychang]

Why are these changes needed?

Create startup/shutdown functions

Related issue number

#4705

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
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[peterychang]

Getting this up for review. I'll see if any other agents need something done and add documentation for this after the holidays

[jackgerrits]

Let's keep it to deactivation initially since there is currently no clear use case for activation but there is for deactivation

[jackgerrits]

Also matter of preference, but I would prefer close

[jackgerrits]

Considering we just want shutdown, would be easier to just iterate _instantiated_agents here instead

[husseinmozannar]

reminder to also update autogen studio code where close is called or create an issue so that victor updates it later

[peterychang]

Let's keep it to deactivation initially since there is currently no clear use case for activation but there is for deactivation

Is there a particular reason not to have the activation portion in place? The behavior for everything right now is just passing, and I could foresee situations where you want a separate initialization component outside the constructor

[jackgerrits]

Let's keep it to deactivation initially since there is currently no clear use case for activation but there is for deactivation

Is there a particular reason not to have the activation portion in place? The behavior for everything right now is just passing, and I could foresee situations where you want a separate initialization component outside the constructor

Initialization should happen in the agent's factory so the functionality is already provided and then just adds a different way to achieve the same thing without a clear use case.