satlab: Add USB Image downloader to Dockerfile

Add USB Image downloader to dockerfile and install it

BUG:b:364955403
TEST= docker build . -t ${TAG} -f Dockerfile
    docker run -t -d ${TAG}
    docker exec -it ${ID} image_downloader --help

Change-Id: I926174114a9e304913cfedce9d9fa7d8737ff518
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/xolabs-common-core/+/6042692
Reviewed-by: Keith Haddow <haddowk@chromium.org>
Commit-Queue: Michal Matyjek <mmatyjek@google.com>
Auto-Submit: Brian Nemec <bnemec@google.com>
Tested-by: Brian Nemec <bnemec@google.com>
Reviewed-by: Michal Matyjek <mmatyjek@google.com>