Refactor examples to remove use of deprecated winit functions

[apekros]

Just a quick draft, as I was not sure if you would be picky about the structure in the examples. I've just refactored the existing Example to be ExampleInner which is now contained within a new Example struct which holds the window/inner. I did this to minimise the amount of changes.

I can however go for a different approach and keep the Example struct, but instantiate everything within new() that does not require a Window, and then have a secondary instantiate (no good name comes to mind right now), that can be called with a window on ApplicationHandler::resumed()

Will await your thoughts before applying this across all the examples

[kvark]

Ideally, the struct Example doesn't care about the window, yeah. If you can prototype the (more invasive) alternative that would be awesome!

[apekros]

Ideally, the struct Example doesn't care about the window, yeah. If you can prototype the (more invasive) alternative that would be awesome!

I'll look into if I can do it without the window being contained within Example but looks like that's what the winit team envisions it as being in their examples.