Windows gpui platform (#8490)

First implementation of gpui platform for Windows.

Release Notes:

- N/A

---------

Co-authored-by: Marshall Bowers <elliott.codes@gmail.com>

crates/gpui/src/platform/windows.rs

@@ -0,0 +1,13 @@
+mod dispatcher;
+mod display;
+mod platform;
+mod text_system;
+mod util;
+mod window;
+
+pub(crate) use dispatcher::*;
+pub(crate) use display::*;
+pub(crate) use platform::*;
+pub(crate) use text_system::*;
+pub(crate) use util::*;
+pub(crate) use window::*;