Dockerize Builds (#712)
* Add support for building docker images
Sample command to build docker image:
$ docker build -t torch-xla -f docker/Dockerfile .
The docker/cloudbuild.yaml source controls the request sent to
cloudbuild for submitting build jobs for building docker images and
collecting the wheel artifacts. Can be run as:
$ gcloud --project=jysohntpu builds submit --config docker/cloudbuild.yaml . --async
-> with -f docker/Dockerfile used on docker/cloudbuild.yaml in build
step
