feat: enhance error handling and reasoning mechanisms across middleware

- Improve error handling across multiple middleware and adapter components, ensuring consistent error response formats in JSON.
- Enhance the functionality of request conversion functions by including context parameters and robust error wrapping.
- Introduce new features related to reasoning content in the messaging model, providing better customization and explanations in the documentation.

relay/adaptor/openai/util.go

@@ -3,6 +3,7 @@ package openai
 import (
 	"context"
 	"fmt"
+	"strings"
 
 	"github.com/songquanpeng/one-api/common/logger"
 	"github.com/songquanpeng/one-api/relay/model"