Menu a11y fixes

[soniktrooth]

We surfaced some a11y fixes for menus in EECS particularly to do with role="menu" and role="menuitem" which are actually meant for web apps. We should remove these from the theme functions they are currently in.

see https://kalamuna.atlassian.net/browse/EECS-510

[andrewmallis]

It would be interesting to see what the a11y people at UCB do say about our standard bootstrap patterns for kalatheme menus.

http://sinberbest.berkeley.edu is a UCB property. Perhaps we can ask for a review of that site?

[soniktrooth]

@andrewmallis I already know what they would say. The fixes that I will make with this issue will bring us inline with vanilla Bootstrap, however there are still some issues with roles. I have doubts that we will have the bandwidth to address too much of this given that BS 4 is close and efforts really need to be concentrated on D8.