Allow for different modes of sub-agent workflows. #344
Description
There are a few different ways that one can work with sub-agents. We should make this configurable and also document it in the official docusaurs documentation website.
The first mode is "disabled", one does not use sub-agents at all. In this mode, no agent tools should be added to the list of available tools.
The second mode is "sync" and this means that when a sub-agent is created, the parent agent waits until the sub-agent is done before continuing. This should use the agentExecute tool, thus it should be added to the list of tools.
The third mode is "async" and this means that when a sub-agent is created, it runs in the background and the main agent can check in on the sub-agent to see how it is going and can also offer corrections. This uses the agentStart and agentMessage and listAgent tools.