Make Flows/Agents composable in DAP
## Problem
Every Flow and Agent currently has to be built from scratch using our yml configuration language. This also means that there is no way to re-use an Agent or a similar component in multiple flows, instead prompts and configurations would need to be copy-pasted across flows.
There is also no way to dynamically add subagents to an existing agent during runtime as other similar products provide so that users can create their own subagents and easily try them out.
## Desired Outcome
When:
- building Agents/Flows within the AI Gateway
- building Agents/Flows within the AI Catalog
Rather than defining everything from scratch users can reference other components/agents in their newly created definition.
When:
- running Agents/Flows locally
Users can dynamically add additional agents if the flow allows the usage of locally defined subagents.
epic