Adds the broker_ipc crate, which is used for communication & setup tasks
shared between the broker (Windows orchestrator for crosvm & vhost-user
devices) and all other crosvm processes.
BUG=b:232318124
TEST=builds
Change-Id: I17d529305dd348a50574e6c3c082808e97ffff45
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3648474
Reviewed-by: Dennis Kempin <denniskempin@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Noah Gold <nkgold@google.com>
