Support EV_MSC on uinput devices

[ninevra]

As far as I can tell, evdev::uinput::VirtualDeviceBuilder doesn't provide any interface for advertising support for EV_MSC (as well as EV_REP, EV_LED, EV_SND, and EV_PWR) events. This makes it a little hard to make e.g. a virtual keyboard (many (maybe most?) keyboard drivers emit an EV_MSC MSC_SCAN event alongside each EV_KEY event) or a virtual proxy for a physical device (which might want to forward arbitrary events based on what the physical device supports).