gpui: Decouple X11 logic from LinuxPlatform (#7598)

Release Notes:

- Separated Linux platform and X11-specific code, so that we can add
Wayland support now.

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Co-authored-by: Mikayla <mikayla@zed.dev>
266988adeaRoman committed on 2/12/2024, 6:44:34 PM· committed by GitHubparent2e7db57
13 files changedLine totals unavailable