Add windows and mac dev desktops

[MarcoIeni]

Sometimes CI fails on windows or mac and contributors using dev-desktops have no way to reproduce the issue.

It would be nice if we provide dev desktops with windows and mac too.

zulip discussions:

• https://rust-lang.zulipchat.com/#narrow/stream/242791-t-infra/topic/dev-desktops.20for.20macOS.3F
• https://rust-lang.zulipchat.com/#narrow/stream/242791-t-infra/topic/Windows.20dev.20desktops.3F

Alternatives

• Microsoft provides VMs for development for x86: https://developer.microsoft.com/en-us/windows/downloads/virtual-machines/
• Allow running CI locally, i.e. the ability to reproduce jobs in CI locally. Note: this wouldn't work for mac, because Apple doesn't allow running MacOs on non-apple hardware.

[tgross35]

Just poking around, what is needed to make this happen? MacStadium has bare metal machines available https://www.macstadium.com/pricing. I guess Azure is probably the best option for Windows VPS? It looks like that can get somewhat expensive, especially with storage.