Initial kmsdrm support

[StratusFearMe21]

• Tested on all platforms changed
• Compilation warnings were addressed
• cargo fmt has been run on this branch
• cargo doc builds successfully
• Added an entry to CHANGELOG.md if knowledge of this change could be valuable to users
• Updated documentation to reflect any user-facing changes, including notes of platform-specific behavior
• Created or updated an example program if it would help users understand this functionality

(Warning, this PR lists my PR to winit as a dependency)

See my PR to winit

[StratusFearMe21]

Warning: DO NOT MERGE YET. Performance is not where it needs to be at the moment, and it's forcing 60 fps apps to run at 30.

[StratusFearMe21]

Okay, the performance issue is fixed, this PR is ready to be reviewed.

[StratusFearMe21]

I'm pretty confident with this PR at this point. As a functionality test, I ported Alacritty to this PR and now it runs straight from the tty https://github.com/StratusFearMe21/alacritty

[StratusFearMe21]

The only thing I can think of to add is a cursor, but it's not a must

[StratusFearMe21]

Yeah, at this point, I think this is ready to be merged. Im very happy with this PR in its current state.

[madsmtm]

FYI: I think #1435 is going to hit first

[kchibisov]

Given that #1435 got merged you'd need to update it, however EGL can create context from DRM device, not sure what needs here?

[kchibisov]

I'll close it, since I don't understand what else is required for KMS. I was able to use glutin with gbm in the context of smithay just fine to draw my triangle. Maybe vsync handling needs a bit special treatment, but it could be done separately.