Consider add portal-tag-name support to PortForComponent

[foxnewsnetwork]

The Proposition

Consider changing the code at:

https://github.com/minutebase/ember-portal/blob/master/addon/components/portal-for.js#L9

to something like:

'portal-tag-name': 'div',
portalElement() {
  const elementID = portalIdForName(this.get("name"));
  let element = document.getElementById(elementID);

  if (!element) {
    element = document.createElement(this.get('portal-tag-name'));
    element.id = elementID;
  }

  return element;
},

The Reason

This will allow users to customize the element tag name of the created portal, which is particularly useful for yielding into lists, spans, and other such elements

[rlivsey]

👍 I'd quickly merge a PR which added this with a test.