Implement SQLite Store using gorm and relational approach (#1065)

Restructure data handling for improved performance and flexibility. 
Introduce 'G'-prefixed fields to represent Gorm relations, simplifying resource management. 
Eliminate complexity in lookup tables for enhanced query and write speed. 
Enable independent operations on data structures, requiring adjustments in the Store interface and Account Manager.

management/cmd/migration_down.go

@@ -0,0 +1,66 @@
+package cmd
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+	"path"
+
+	"github.com/netbirdio/netbird/management/server"
+	"github.com/netbirdio/netbird/util"
+	log "github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+)
+
+var shortDown = "Rollback SQLite store to JSON file store. Please make a backup of the SQLite file before running this command."
+
+var downCmd = &cobra.Command{
+	Use:     "downgrade [--datadir directory] [--log-file console]",
+	Aliases: []string{"down"},
+	Short:   shortDown,
+	Long: shortDown +
+		"\n\n" +
+		"This command reads the content of {datadir}/store.db and migrates it to {datadir}/store.json that can be used by File store driver.",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		flag.Parse()
+		err := util.InitLog(logLevel, logFile)
+		if err != nil {
+			return fmt.Errorf("failed initializing log %v", err)
+		}
+
+		sqliteStorePath := path.Join(mgmtDataDir, "store.db")
+		if _, err := os.Stat(sqliteStorePath); errors.Is(err, os.ErrNotExist) {
+			return fmt.Errorf("%s doesn't exist, couldn't continue the operation", sqliteStorePath)
+		}
+
+		fileStorePath := path.Join(mgmtDataDir, "store.json")
+		if _, err := os.Stat(fileStorePath); err == nil {
+			return fmt.Errorf("%s already exists, couldn't continue the operation", fileStorePath)
+		}
+
+		sqlstore, err := server.NewSqliteStore(mgmtDataDir, nil)
+		if err != nil {
+			return fmt.Errorf("failed creating file store: %s: %v", mgmtDataDir, err)
+		}
+
+		sqliteStoreAccounts := len(sqlstore.GetAllAccounts())
+		log.Infof("%d account will be migrated from sqlite store %s to file store %s",
+			sqliteStoreAccounts, sqliteStorePath, fileStorePath)
+
+		store, err := server.NewFilestoreFromSqliteStore(sqlstore, mgmtDataDir, nil)
+		if err != nil {
+			return fmt.Errorf("failed creating file store: %s: %v", mgmtDataDir, err)
+		}
+
+		fsStoreAccounts := len(store.GetAllAccounts())
+		if fsStoreAccounts != sqliteStoreAccounts {
+			return fmt.Errorf("failed to migrate accounts from sqlite to file[]. Expected accounts: %d, got: %d",
+				sqliteStoreAccounts, fsStoreAccounts)
+		}
+
+		log.Info("Migration finished successfully")
+
+		return nil
+	},
+}