feat: support Gemini openai compatible api

relay/adaptor/geminiv2/constants.go

@@ -0,0 +1,15 @@
+package geminiv2
+
+// https://ai.google.dev/models/gemini
+
+var ModelList = []string{
+	"gemini-pro", "gemini-1.0-pro",
+	// "gemma-2-2b-it", "gemma-2-9b-it", "gemma-2-27b-it",
+	"gemini-1.5-flash", "gemini-1.5-flash-8b",
+	"gemini-1.5-pro", "gemini-1.5-pro-experimental",
+	"text-embedding-004", "aqa",
+	"gemini-2.0-flash", "gemini-2.0-flash-exp",
+	"gemini-2.0-flash-lite-preview-02-05",
+	"gemini-2.0-flash-thinking-exp-01-21",
+	"gemini-2.0-pro-exp-02-05",
+}

relay/adaptor/geminiv2/main.go

@@ -0,0 +1,14 @@
+package geminiv2
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/songquanpeng/one-api/relay/meta"
+)
+
+func GetRequestURL(meta *meta.Meta) (string, error) {
+	baseURL := strings.TrimSuffix(meta.BaseURL, "/")
+	requestPath := strings.TrimPrefix(meta.RequestURLPath, "/v1")
+	return fmt.Sprintf("%s%s", baseURL, requestPath), nil
+}