move metrics to telemetry; copy to client config

better api example, add telemetry documentation

prevent against flaky test due to timing/initialization issues

Always purge stopped containers

Fix repo name passed to docker credential helpers

Update go-getter

* Vendor consul-template

Fixes https://github.com/hashicorp/nomad/issues/3133

* changelog

This PR fixes the server url passed to docker credential helpers and
fixes stderr capture.

Fixes https://github.com/hashicorp/nomad/issues/2957

Fixes https://github.com/hashicorp/nomad/issues/3154

Integration test for round tripping a job.

* Parse Docker mounts correctly

This PR fixes the parsing of Docker mounts and adds testing to ensure no
regressions.

Fixes https://github.com/hashicorp/nomad/issues/3156

* Review feedback

Add support for tagged metrics

Initial ACL enforcement framework