* Making pull activity timeout configurable in Docker plugin config, first pass

* Fixing broken function call

* Fixing broken tests

* Fixing linter suggestion

* Adding documentation on new parameter in Docker plugin config

* Adding unit test

* Setting min value for pull_activity_timeout, making pull activity duration a private var

cli: sequence cli.Ui operations

Fixes a bug where if a command flag parsing errors, the resulting error
and help usage messages get interleaved in unexpected and non-user
friendly way.

The reason is that we have flag parsing library effectively writes to
ui.Error in a goroutine.  This is problematic: first, we lose the sequencing between help
usage and error message; second, cli.Ui methods are not concurrent safe.

Here, we introduce a custom error writer that buffers result and calls
ui.Error() in the write method and in the same goroutine.

For context, we need to wrap ui.Error because it's line-oriented, while
flags library expects a io.Writer which is bytes oriented.

env_aws: Disable Retries and set Session cfg

Co-Authored-By: Mahmood Ali <mahmood@hashicorp.com>

tests: remove trace statements from nodeDrainWatcher.watch

Adds Windows targets to the client/allocs metrics tests. Removes the
`allocstats` test, which covers less than these tests and is now
redundant.

Adds a firewall rule to our Windows instances so that the prometheus
server can scrape the Nomad HTTP API for metrics.

Avoid logging in the `watch` function as much as possible, since
it is not waited on during a server shutdown. When the logger
logs after a test passes, it may or may not cause the testing
framework to panic.

More info in:
https://github.com/golang/go/issues/29388#issuecomment-453648436

Previously, Nomad used hand rolled HTTP requests to interact with the
EC2 metadata API. Recently however, we switched to using the AWS SDK for
this fingerprinting.

The default behaviour of the AWS SDK is to perform retries with
exponential backoff when a request fails. This is problematic for Nomad,
because interacting with the EC2 API is in our client start path.

Here we revert to our pre-existing behaviour of not performing retries
in the fast path, as if the metadata service is unavailable, it's likely
that nomad is not running in AWS.

connect: canonicalize before adding sidecar

driver: allow disabling log collection

Update go-multierror library

multierror library changed formatting slightly.

To pick up https://github.com/hashicorp/go-multierror/pull/28

I unintentionally introduced a flapping test in #6817. The
draining status of the node will be randomly chosen and
that flag takes precedence over eligibility. This forces
the draining flag to be false rather than random so the
test should no longer flap.

See here for an example failure:
https://circleci.com/gh/hashicorp/nomad/26368

executor: stop joining executor to container cgroup

Also make Connect related fixes more consistent in the changelog. I
suspect users won't care if a Connect related fix is in the server's
admission controller or in the client's groupservice hook or somewhere
else, so I think grouping them by `consul/connect:` makes the most
sense.

Fixes #6853

Canonicalize jobs first before adding any sidecars. This fixes a bug
where sidecar tasks were added without interpolated names and broke
validation. Sidecar tasks must be canonicalized independently.

Also adds a group network to the mock connect job because it wasn't a
valid connect job before!

Add notarization details to changelog

Use debug logging for scheduler internals

There are two changes here, and some caveats/commentary:

1. The “State“ table column was actually sorting only by status. The state was not an actual property, just something calculated in each client row, as a product of status, isEligible, and isDraining. This PR adds isDraining as a component of compositeState so it can be used for sorting.

2. The Sortable mixin declares dependent keys that cause the sort to be live-updating, but only if the members of the array change, such as if a new client is added, but not if any of the sortable properties change. This PR adds a SortableFactory function that generates a mixin whose listSorted computed property includes dependent keys for the sortable properties, so the table will live-update if any of the sortable properties change, not just the array members. There’s a warning if you use SortableFactory without dependent keys and via the original Sortable interface, so we can eventually migrate away from it.

UI: Unclosed log streams

We currently log an error if preemption is unable to find a suitable set of
allocations to preempt. This commit changes that to debug level since not finding
preemptable allocations is not an error condition.

Refactor the metrics end-to-end tests so they can be run with our e2e
test framework. Runs fabio/prometheus and a collection of jobs that
will cause metrics to be measured. We then query Prometheus to ensure
we're publishing those allocation metrics and some metrics from the
clients as well.

Includes adding a placeholder for running the same tests on Windows.

tests: parallelize state store tests

Stop joining libcontainer executor process into the newly created task
container cgroup, to ensure that the cgroups are fully destroyed on
shutdown, and to make it consistent with other plugin processes.

Previously, executor process is added to the container cgroup so the
executor process resources get aggregated along with user processes in
our metric aggregation.

However, adding executor process to container cgroup adds some
complications with much benefits:

First, it complicates cleanup.  We must ensure that the executor is
removed from container cgroup on shutdown.  Though, we had a bug where
we missed removing it from the systemd cgroup.  Because executor uses
`containerState.CgroupPaths` on launch, which includes systemd, but
`cgroups.GetAllSubsystems` which doesn't.

Second, it may have advese side-effects.  When a user process is cpu
bound or uses too much memory, executor should remain functioning
without risk of being killed (by OOM killer) or throttled.

Third, it is inconsistent with other drivers and plugins.  Logmon and
DockerLogger processes aren't in the task cgroups.  Neither are
containerd processes, though it is equivalent to executor in
responsibility.

Fourth, in my experience when executor process moves cgroup while it's
running, the cgroup aggregation is odd.  The cgroup
`memory.usage_in_bytes` doesn't seem to capture the full memory usage of
the executor process and becomes a red-harring when investigating memory
issues.

For all the reasons above, I opted to have executor remain in nomad
agent cgroup and we can revisit this when we have a better story for
plugin process cgroup management.

It has been decided we're going to live in a many core world.
Let's take advantage of that and parallelize these state store
tests which all run in memory and are largely CPU bound.

An unscientific benchmark demonstrating the improvement:

[mp state (master)] $ go test
PASS
ok  	github.com/hashicorp/nomad/nomad/state	5.162s

[mp state (f-parallelize-state-store-tests)] $ go test
PASS
ok  	github.com/hashicorp/nomad/nomad/state	1.527s

add 6828 to changelog