Have the container image launch buildbot-worker upon deployment

[brettcannon]

Need to make sure that once the container is live it is all set to go automatically. That way anyone can make a change here and have it live w/o permission issues.

[brettcannon]

https://devguide.python.org/testing/new-buildbot-worker/#conventional-always-on-machines

[brettcannon]

Might need to do this in a shell script for #3 to pass in the values via environment variables from something like Key Vault. Otherwise the values need to be present at the time of container creation instead of container execution.