deleteTemplates(templateIds, externalOnly) {
    if (!externalOnly)
      externalOnly = true;
    if (!templateIds || templateIds === "*")
      templateIds = [...this.routeIds];
    if (!Array.isArray(templateIds))
      templateIds = [templateIds];
    templateIds.forEach((routeId) => {
      if (externalOnly === true && !this.isRouteExternal(routeId))
        return;
      this.unloadTemplate(routeId, externalOnly);
    });
  }
Remove ALL templates from the DOM (optionally external templates only)
@param {Array<string>=} templateIds OPTIONAL, default=ALL. Array of template (route) id's to remove
@param {boolean=} externalOnly OPTIONAL, default=true. If true only remove if routeId is an external template