[Feature request] Allow placeholder for table editors

There is no native way to define placeholder for a text input (and others) editor in tables.

It would be nice to have it.

Actually I need a specific editor for that :

webix.editors.text_with_placeholder = webix.extend(
        render: function () {
            const elem = webix.editors.text.render.apply(this, arguments);
            elem.firstChild.setAttribute('placeholder', this.config.placeholder);
            return elem;

Thanks for your suggestion, we will consider it as a possible feature in the future!