Comment 2 for bug 1945498

Here's a branch that makes the nav menu responsive: https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/sleary/LP1945498-responsive-navbar

The keyboard events are verbose, but the ng-bootstrap Collapse functionality (https://ng-bootstrap.github.io/#/components/collapse/examples#navbar) was written as a simple click handler, which doesn't support keyboard users, so here we are. If nothing else, this demonstrates why I've spent so much time converting links to buttons elsewhere in the interface.