Check license expiration, disable license and notify administrator (#14420)

* Check license expiration and notify administrator

app/license.go

@@ -158,6 +158,8 @@ func (a *App) RemoveLicense() *model.AppError {
 		return nil
 	}
 
+	mlog.Info("Remove license.", mlog.String("id", model.SYSTEM_ACTIVE_LICENSE_ID))
+
 	sysVar := &model.System{}
 	sysVar.Name = model.SYSTEM_ACTIVE_LICENSE_ID
 	sysVar.Value = ""