Migrate to Windows-rs from winapi

[Elabajaba]

Is your feature request related to a problem? Please describe.
winapi-rs should probably be considered dead at this point, and Microsoft seems to have settled on windows-rs as the officially supported Windows api bindings. (and have deprecated all the other ones they were experimenting with).

Describe the solution you'd like
Migrate all the winapi code and dependencies to windows-rs.

Additional context
I believe this was previously blocked on a combination of windows-rs being immature, and Mozilla having to get windows-rs approved internally. Windows-rs seems to have settled down a lot, and I'm not sure whether or not Mozilla has okayed it, or if that's even still considered a blocker these days.

[jrmuizel]

It seems like there's still a lot of churn happening: microsoft/windows-rs#2156. We don't really want to end up with a bunch of different versions of windows-rs vendored into the mozilla tree so I think we'll need to wait longer for things to settle more.

[cwfitzgerald]

Copying what I said on matrix last night for long term transparency on the reasoning for the switch and why it isn't possible at this time:

wgpu is going to need more modern dx12 features at some point (including access to new windows 11 apis). winapi, as it stands, doesn't offer bindings to any of these because development died about 2 years ago. winapi is extensable though as they do export their macros. So we can add bindings to these things to d3d12-rs, it just means we have to manually write them.

Before we commit to that, if it would be possible to upgrade to the new, "en vogue" windows bindings it would be good to do so. If we can't due to one of a variety of reasons, that's fine, we just need to expand our bindings when the time comes for us to have newer features

From the comments we've gotten from @jimblandy, @kdashg, and jrmuizel it seems like it's not possible at this point - which is fine, we just should commit to our stance while windows-rs, moz, etc all figure out what's going on wrt windows bindings

[cwfitzgerald]

There's also a standalone PR retep998/winapi-rs#812 that never got merged that we could yank.

[Elabajaba]

Windows-rs maintainers have stated they're going to slow down their cadence and release new windows versions "as necessary", instead of a regular monthly release (but still at a faster rate than the every ~6 months of windows-sys).

There's also been work on updated directx bindings (microsoft/DirectX-Headers#79 and microsoft/DirectX-Headers#82 for the initial legwork), though I'm not sure what the timeline on that might be, or if those would be released as part of windows-rs, or as a separate crate.

[MarijnS95]

@Elabajaba fyi I've closed those DirectX-Headers PRs, the headers are now instead directly consumed by win32metadata and windows-rs so the Agility SDK is immediately available in the official windows crate 🎉

[Elabajaba]

I'm not sure what exact APIs we need, but windows-bindgen now exists and lets us generate our own (minimal) windows bindings if we want. (see RustAudio/cpal#778 for an example)

windows-core also exists now, not really sure what it is exactly. It seems to be a "small" base crate that you use when generating bindings?