Remove Windows libraries from Rust source package

[Zixing Liu]

We want to remove Windows libraries (mostly windows-sys and friends) from the Rust source package.

They contain binary blobs and auto-generated code that consume much storage space (~700 MiB).
Removing them also makes the source package easier to audit.

[Zixing Liu (liushuyu-011)]

Preliminary packages were uploaded to https://launchpad.net/~liushuyu-011/+archive/ubuntu/rust-updates-1.71/+packages.
And also, its corresponding source at https://git.launchpad.net/~canonical-foundations/ubuntu/+source/rustc/tree/?h=merge-1.71.
You can find the autopkgtest results on this page: https://autopkgtest.ubuntu.com/results/autopkgtest-mantic-liushuyu-011-rust-updates-1.71/?format=plain (tests that represent library removal have a timestamp dated after 20230912).

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Lintian report:

E: rustc source: field-too-long Vendored-Sources-Rust (10433 chars > 5000)
W: rustc source: mismatched-override missing-license-paragraph-in-dep5-copyright debian/copyright mpl-2.0+ [debian/source/lintian-overrides:15]
W: rustc source: missing-license-paragraph-in-dep5-copyright mpl-2.0+ [debian/copyright:2044]
W: rustc source: unknown-field Vendored-Sources-Rust
N: 0 hints overridden; 1 unused override
N: Some overrides were ignored.
N: Use --verbose for more information.
Finished running lintian.