refactor: Moves the LLM factory initialization logic to the dao package. (#13476)

### What problem does this PR solve?

refactor: Moves the LLM factory initialization logic to the `dao`
package.

Removes the `init_data` package and integrates the LLM factory
initialization functionality into the `dao` package.
Adds a `utility` package to provide general utility functions.
Updates `server_main.go` to use the new initialization path.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

Co-authored-by: Jin Hai <haijin.chn@gmail.com>

cmd/server_main.go

@@ -6,8 +6,7 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
-	"ragflow/internal/common"
-	"ragflow/internal/init_data"
+  "ragflow/internal/common"
 	"ragflow/internal/server"
 	"ragflow/internal/utility"
 	"strings"
@@ -67,7 +66,7 @@ func main() {
 	}
 
 	// Initialize LLM factory data models from configuration file
-	if err := init_data.InitLLMFactory(); err != nil {
+	if err := dao.InitLLMFactory(); err != nil {
 		logger.Error("Failed to initialize LLM factory", err)
 	} else {
 		logger.Info("LLM factory initialized successfully")