feat: add GetLoginCount() to support get login count

enforcer.go

@@ -378,6 +378,13 @@ func (e *Enforcer) GetLoginId(ctx ctx.Context) (string, error) {
 	return str, nil
 }
 
+func (e *Enforcer) GetLoginCount(id string) int {
+	if session := e.GetSession(id); session != nil {
+		return session.TokenSignList.Len()
+	}
+	return 0
+}
+
 func (e *Enforcer) Banned(id string, service string) error {
 	panic("implement me ...")
 }

enforcer_interface.go

@@ -16,6 +16,7 @@ type IEnforcer interface {
 	IsLogin(ctx ctx.Context) (bool, error)
 	IsLoginById(id string) (bool, error)
 	GetLoginId(ctx ctx.Context) (string, error)
+	GetLoginCount(id string) int
 
 	Replaced(id string, device string) error
 	// Banned TODO