Rename crates_vendor_manifests to cvm to shorten windows path lengths (…

…#1944)

The `LINK : fatal error LNK1181: cannot open input file 'windows.0.48.0.lib` in https://buildkite.com/bazel/bazel-at-head-plus-downstream/builds/2983#0187c0e7-1c1b-40ca-9a81-6f2c261bfe9e from #1938 seems to come from too long a path; I believe the `windows.0.48.0.lib` file should be under `C:\\b\\ng6ta375\\execroot\\__main__\\bazel-out/x64_windows-opt-exec-ST-f007e4e0eadc/bin/external/crates_vendor_manifests__windows_x86_64_msvc-0.48.0/windows_x86_64_msvc_build_script_.exe.runfiles/crates_vendor_manifests__windows_x86_64_msvc-0.48.0/lib`, which, together with the file's name surpasses the Windows filepath limit of 260 characters.

I only changed a `crates_vendor_manifests` repository to `cvm`, and I needed to run `bazel run @//vendor_local_pkgs:crates_vendor`, `bazel run @//vendor_local_manifests:crates_vendor`, `bazel run @//vendor_remote_manifests:crates_vendor` afterwards. This seems to have triggered some crate version updates, e.g `rustix-0.37.14 -> rustix-0.37.15` I'm not sure if that's expected.