feat: convert gemini format to openai chat completions

relay/channel/volcengine/adaptor.go

@@ -23,6 +23,11 @@ import (
 type Adaptor struct {
 }
 
+func (a *Adaptor) ConvertGeminiRequest(*gin.Context, *relaycommon.RelayInfo, *dto.GeminiChatRequest) (any, error) {
+	//TODO implement me
+	return nil, errors.New("not implemented")
+}
+
 func (a *Adaptor) ConvertClaudeRequest(*gin.Context, *relaycommon.RelayInfo, *dto.ClaudeRequest) (any, error) {
 	//TODO implement me
 	panic("implement me")