cli: add policy list and info to new scaling cmd.

cli: move tests to use NewMockUi func.

consul/connect: trigger update as necessary on connect changes

job, task group, and task IDs should not allow null characters

This PR fixes a long standing bug where submitting jobs with changes
to connect services would not trigger updates as expected. Previously,
service blocks were not considered as sources of destructive updates
since they could be synced with consul non-destructively. With Connect,
task group services that have changes to their connect block or to
the service port should be destructive, since the network plumbing of
the alloc is going to need updating.

Fixes #8596 #7991

Non-destructive half in #7192

updated CHANGELOG and upgrade guide

[doc] fix deprecated port_map example

Add service discovery integration to the existing consul-template E2E test,
and verify both service and key updates force re-rendering. Fixes flakiness by
using the longer default wait config we use elsewhere.

Removes our last direct dependency on gomega.

docs: Format docs website code and mdx

Provisions vault with the policies described in the Nomad Vault integration
guide, and drops a configuration file for Nomad vault server configuration
with its token. The vault root token is exposed to the E2E runner so that
tests can write additional policies to vault.

This adds the ability to detail scaling policies via the CLI.

Use 32-byte key for gossip encryption to enable AES-256 

Co-authored-by: Seth Hoenig <shoenig@hashicorp.com>

docs: document docker signal fix, add tests

So a null logger is used to avoid the problem.

This PR adds a version specific upgrade note about the docker stop
signal behavior. Also adds test for the signal logic in docker driver.

Closes #8932 which was fixed in #8933

The `-var-file` flag for loading variables into Terraform overlays the default
variables file if present. This means that variables that are set in the
default variables file will take precedence if the overlay file does not have
them set.

Set `nomad_acls` and `nomad_enteprise` to `false` in the dev cluster.

Tests: fix some tests for Ubuntu 18.04

`nomad volume detach volume-id 00000000-0000-0000-0000-000000000000` produces an API call containing the UUID as part of the query string. This is the only way the API accepts the request correctly - if you pass it in the payload you get `detach requires node ID`

On host with systemd-resolved, we copy /run/systemd/resolve/resolv.conf
actually.

In systemd-resolved hosts with no DNS customizations, the docker driver
DNS setting should be compared to /run/systemd/resolve/resolv.conf while
exec/java drivers should be compared to /etc/resolv.conf.

When system-resolved is enabled, /etc/resolv.conf is a stub that points
to 127.0.0.53. Docker avoids this stub because this address isn't
accessible from the container.  The exec/java drivers that don't create
network isolations use the stub though in the default configuration.

On the failover path, copy the permission bits (a.k.a. file mode),
specially the execution bit.

My latest Vagrant box contains an empty cgroup name that isn't used for
isolation:

```
$ cat /proc/self/cgroup  | grep ::
0::/user.slice/user-1000.slice/session-17.scope
```