Bring back Enter/Esc for default/cancel menu options

Most of the popup menus (restart flight, back to main menu, etc) used to have Enter and Esc assigned to default & cancel options. I know this was removed a long time ago, and I reported it on zendesk back the but I guess nobody else wants it? We are now FORCED to use the mouse to navigate the UI.

Ditto Esc to resume from pause menu.