[NEOS-1447] Investigate using protoc-gen-connect-openai

[nickzelei]

https://github.com/sudorandom/protoc-gen-connect-openapi

This seems to be a new project that is tailored to generating high quality openai specs based off of connect protos.

This could be useful for us for using other tools to generate openai-based clients.

We could maybe use this to feed into hashicorp's terraform provider generator to reduce TF provider maintenance burden.

_{From SyncLinear.com | NEOS-1447}