[WIP] Wire up new mobile nav

References #3810

With GUI2, there's now a number of places to open the mobile navigation menu. This handles those clicks.

It's labeled as WIP, so please tear it apart.
Sorry to keep pinging you on this. Can we get a better name than "mobileInteractions", which is kind of a holdover from the old days? This looks more like `setupNavMenuClosingOnResize` which is a terrible name, but something along those lines. didn't the "removexxx" below