Follow up AI Plugin for Moodle: StdIO OpenAI Compatible plugin

Create a Plugin for Moodle.
- [x] This plugin should communicate with a OpenAI Compatible endpoint.
- [x] It should configure credentials only using ENV params only. Not Credentials configuration from the dashboard.
- [ ] It should use the `response` endpoint of the OpenAPI interface
- [x] It should do requests by StdIO

Doing this would mean having a tiny rust app, running as a side process to the moodle in the same container
- [x] This implies a small rust server listening and writing to stdio
- [x] Use clap for configuration
- [ ] Use https://crates.io/crates/openai
- [x] Optimize API Calls by using summarization where needed