Auto merge of #20658 - kvark:deglify, r=emilio

Make gleam optional for compositor, switch various names from glutin to winit

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The PR goes an extra step towards discriminating GL to a level of an optional dependency. This would ease up the transition to gfx-hal when the time calls for it, and upstreams some of the patches we've been using locally, cleans up some of the old cruft along the way.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach build-geckolib` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #20612

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____ it's just refactoring

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