Instead of requiring crosvm to be checked out via the chromeos manifest
to access dependencies in the ChromeOS monorepo, this change adds
git submodules to third_party/.
The CI scripts and Cargo.toml are updated to use the new paths.
BUG=b:194336213
TEST=git clone --recursive https://chromium.googlesource.com/chromiumos/platform/crosvm
cd crosvm
cargo test
./test_all
./ci/kokoro/simulate_all
Change-Id: I9859d18176e21909ac3a140976fbd67cc14129bb
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3049003
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Dennis Kempin <denniskempin@google.com>
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
