Vendor consul & consul-template

Improve artifact download error message

Don't take a reference a var in a loop

disk is not a supported entry at task level

Removed the reference to `disk` in the `resources` overview statement

Stop Vault token renew on task exit

Fix dispatch of periodic job

Various fixes for setting user/group of task

Access Node Meta and Attrs in template

Fix periodic job state

Proper reference counting through task restarts

This PR fixes an oversight in which the client would attempt to renew a
token even after the task exits.

Fixes https://github.com/hashicorp/nomad/issues/2475

Fixes #2491

Mention Nomad CLI remote usage

Fix TLS use in AllocFS API and region/dc detection

Added information about `NOMAD_ADDR` environment variable for Nomad CLI remote usage.

This PR fixes an issue in which when a periodic and parameterized job
was dispatched, an allocation would be immediately created.

Fixes https://github.com/hashicorp/nomad/issues/2470

This PR allows accessing the Node's attributes and metadata as in a
template.

```
template {
    data = "{{ env \"attr.unique.network.ip-address\" }}"
    destination = "local/out"
}
```

Remove incorrect list of supported protocols