Styles for a specific MenuItem

### Issue type

**I'm submitting a ...** (check one with "x")

* [ ] bug report
* [x] feature request

### Issue description

**Current behavior:**

Right now every MenuItem must follow the same set of styles.

**Expected behavior:**

It would be nice if there's a way to set style for specific menuItem. (For example, grey out items that user doesn't have access to)