Expose more Winit events

[khionu]

I'm writing a Virtual Tabletop, and I'd like people to be able to drag assets directly into the window, but this requires a specific event.

[hannah-w-cs]

Hmm, this shouldn't be too hard. It would be good to get some feedback on which events from winit::event::WindowEvent should be exported in coffee::input::window::Event? there's also winit::event which has some useful events, some of which are already hooked to coffee events. since this library is opinionated about some things, not all the events should be exposed, right? but many of them could be without too much trouble. Also what do y'all think about the events handled by winit_input_helper?
(i'm pretty new to rust and this library especially, so these are just some thoughts)
(@khionu nice profile pic, trans rights!!!!!!!!!)