Hard to read lengthy prompt in agent json file

Json format doesn't support multiline string. The [prompt](https://github.com/aws/amazon-q-developer-cli/blob/main/schemas/agent-v1.json) field defined in agent json file is a string type.

I could think of two solutions. Is any of them supported now or in the near future?
1. Be able to config the agent with `yaml` format which supports multiline string.
2. Be able to reference prompts, for example,
```
{
"$schema": "...",
"name": "...",
"description": "...",
"prompt": "@my_first_prompt"
```
The `my_first_prompt` is defined in `.aws/amazonq/prompts/my_first_prompt.md`