Fix old services not getting removed from consul on update

Token revocation and keeping only a single Vault client active among servers

Implemented SetPrefferingNodes in stack

Merging telemetry configs

Fixed grammar

Changed "your" to "you" to become "...what would happen if you ran the updated job:"

Instead just remove all associated services on shutdown.

Fixes #1661

Update vendor package shirou/gopsutil

* resolve #1392
* pull in the fix for shirou/gopsutil/#249 which updates
  the Linux driver for `cpu` to set `cpu.Mhz` to the maximum
  clock-speed of the CPU, if that's available

VaultClient for Nomad client's interactions with Vault

Remove rpc*, connPool, node and region from vaultclient.

Server side changes for sticky volumes

Make alloc-status and node-status work without access to stats

Token revocation

Remove from the statestore

Revoke tokens

Don't error when Vault is disabled as this could cause issue if the operator ever goes from enabled to disabled

update server interface to allow enable/disable and config loading

test the new functions

Leader revoke

Use active

Web copy fixes