Have hcsshim use the code from this repo.

[KenGordon]

This code was taken from the hcsshim repo to simplify releases. To avoid duplication have hcsshim consume it from here.

[anmaxvl]

I think we want it the other way around... I've opened a PR to address it #7.

[BryceDFisher]

microsoft/hcsshim#2298