🔧 💥 #235: Extended the non-streaming chat error schema with new fields to give clients more context around the error (#236)

- Introduced a new error type to hold useful context like HTTP response status, error name, message
- If all providers are unavailable, we are not throwing 500 error anymore but 503
- Start throwing unknown_error with 500 status on unexpected exceptions
- Predefined all static HTTP errors instead of creating them every time they occur
- Introduced the name field on the error schema
- Changed the req/response schema to snake_case (hopefully, to stick with it forever)
- Removed Bruno collections (it doesn't cover all our needs like websocket or gRPC protocol)
- Moved all schemas to `api/schema` package
- Made router list API opaque
- Changed the field name for overrides not to clash with defined statements in some languages

Author: roma-glushko

README.md

@@ -94,7 +94,7 @@ See [API Reference](https://glide.einstack.ai/api-reference/introduction) for mo
         "role": "user",
         "content": "Where was it played?"
       },
-  "messageHistory": [
+  "message_history": [
       {"role": "system", "content": "You are a helpful assistant."},
       {"role": "user", "content": "Who won the world series in 2020?"},
       {"role": "assistant", "content": "The Los Angeles Dodgers won the World Series in 2020."}