feat(docker): replace image link and fix some usages of scripts

[mask-pp]

docker-compose change, reference link:

1. replace the image link from gcr.io/xxx to gcr.dockerproxy.com, so that users can pull images without a Google Cloud account.

shell script changes:

1. In POSIX sh, [[ ]] is undefined.
2. In POSIX sh, == in place of = is undefined.
3. Use -n instead of ! -z.
4. Double quote to prevent globbing and word splitting.

[davidtaikocha]

Could u rebase this PR on the katla branch?

[mask-pp]

Could u rebase this PR on the katla branch?

Changed in a new PR.