A few connect examples reference a fake 'test/test' image.
By replacing those with `hashicorpnomad/counter-api` we can
turn them into runnable examples.
This changeset adds documentation changes for the new
`proxy.expose` stanza as well as the `check.expose` parameter.
The examples are centered around proposed changes for the "countdash"
`dashboard-service` in [demo-consul-101](github.com/hashicorp/demo-consul-101/pull/6).
The dashboard service will now serve two additonal endpoints
- `/health/api`
- `/metrics`
which should serve nicely as expose-able paths.
