We use the education team's "countdash" demo in many places
to showcase Nomad's Consul Connect integration. This change
adds a Dockerfile for each of `counter-dashboard` and
`counter-api` that can be used to build artifacts to publish
to Nomad's Docker Hub organization.
The recent "0.0.3" release of the `countdash` demo includes
changes we want in order to demo task group service checks.
