unloadTemplate(routeId, externalOnly) {
    if (!externalOnly)
      externalOnly = true;
    if (!routeId || !this.isRouteExternal(routeId))
      return;
    if (externalOnly === true && !this.isRouteExternal(routeId))
      return;
    const chkTemplate = document.querySelector(`#${routeId}`);
    if (chkTemplate)
      chkTemplate.remove();
  }
Remove a template from the DOM (optionally external templates only)
@param {string} routeId REQUIRED. The route id of the template to remove (templates are ID's by their route id)
@param {boolean=} externalOnly OPTIONAL, default=true. If true only remove if routeId is an external template