This PR implements Nomad built-in support for running Consul Connect
terminating gateways. Such a gateway can be used by services running
inside the service mesh to access "legacy" services running outside
the service mesh while still making use of Consul's service identity
based networking and ACL policies.

https://www.consul.io/docs/connect/gateways/terminating-gateway

These gateways are declared as part of a task group level service
definition within the connect stanza.

service {
  connect {
    gateway {
      proxy {
        // envoy proxy configuration
      }
      terminating {
        // terminating-gateway configuration entry
      }
    }
  }
}

Currently Envoy is the only supported gateway implementation in
Consul. The gateay task can be customized by configuring the
connect.sidecar_task block.

When the gateway.terminating field is set, Nomad will write/update
the Configuration Entry into Consul on job submission. Because CEs
are...

If the connect.proxy stanza is left unset, the connection timeout
value is not set but is assumed to be, and may cause a non-fatal NPE
on job submission.

Deflake test-api job, currently failing at around 7.6% (44 out of 578
workflows), by ensuring that test nomad agent use a small dedicated port
range that doesn't conflict with the kernel ephemeral range.

The failures are disproportionatly related to port allocation, where a
nomad agent fails to start when the http port is already bound to
another process. The failures are intermitent and aren't specific to any
test in particular. The following is a representative failure:
https://app.circleci.com/pipelines/github/hashicorp/nomad/13995/workflows/6cf6eb38-f93c-46f8-8aa0-f61e62fe7694/jobs/128169
.

Upon investigation, the issue seems to be that the api freeport library
picks a port block within 10,000-14,500, but that overlaps with the
kernel ephemeral range 32,769-60,999! So, freeport may allocate a free
port to the nomad agent, just to be used by another process before the
nomad agent starts!

This happened for example in
https://app.circleci.com/pipel...

This reverts commit 71396fa721945e55f51bc90ed02522936450209b.

In a few places Nomad was using flag implementations directly
from Consul, lending to Nomad's need to import consul. Replace
those uses with helpers already in Nomad, and copy over the bare
minimum needed to make the autopilot flags behave as they have.

* use full name for events

use evaluation and allocation instead of short name

* update api event stream package and shortnames

* update docs

* make sync; fix typo

* backwards compat not from 1.0.0-beta event stream api changes

* use api types instead of string

* rm backwards compat note that only changed between prereleases

* remove backwards incompat that only existed in prereleases

* Remove Managed Sinks from Nomad

Managed Sinks were a beta feature in Nomad 1.0-beta2. During the beta
period it was determined that this was not a scalable approach to
support community and third party sinks.

* update comment

* changelog

Before, upstreams could only be defined using the default datacenter.
Now, the `datacenter` field can be set in a connect upstream definition,
informing consul of the desire for an instance of the upstream service
in the specified datacenter. The field is optional and continues to
default to the local datacenter.

Closes #8964

The API is missing values for `ReadAllocs` and `WriteAllocs` fields, resulting
in allocation claims not being populated in the web UI. These fields mirror
the fields in `nomad/structs.CSIVolume`. Returning a separate list of stubs
for read and write would be ideal, but this can't be done without either
bloating the API response with repeated full `Allocation` data, or causing a
panic in previous versions of the CLI.

The `nomad/structs` fields are persisted with nil values and are populated
during RPC, so we'll do the same in the HTTP API and populate the `ReadAllocs`
and `WriteAllocs` fields with a map of allocation IDs, but with null
values. The web UI will then create its `ReadAllocations` and
`WriteAllocations` fields by mapping from those IDs to the values in
`Allocations`, instead of flattening the map into a list.

This PR adds the ability to set HTTP headers when downloading
an artifact from an `http` or `https` resource.

The implementation in `go-getter` is such that a new `HTTPGetter`
must be created for each artifact that sets headers (as opposed
to conveniently setting headers per-request). This PR maintains
the memoization of the default Getter objects, creating new ones
only for artifacts where headers are set.

Closes #9306

* Get concrete types out of dynamic payload

wip

pull out value setting to func

* Add TestEventSTream_SetPayloadValue

Add more assertions

use alias type in unmarshalJSON to handle payload rawmessage

shorten unmarshal and remove anonymous wrap struct

* use map structure and helper functions to return concrete types

* ensure times are properly handled

* update test name

* put all decode logic in a single function
Co-authored-by: Kris Hicks <khicks@hashicorp.com>

Co-authored-by: Drew Bailey <2614075+drewbailey@users.noreply.github.com>

state store: call-out to generic update of job recommendations from job update method
recommendations API work, and http endpoint errors for OSS
support for scaling polices in task block of job spec
add query filters for ScalingPolicy list endpoint
command: nomad scaling policy list: added -job and -type

Adding gateway name eases HCLv2 parsing. This field is only used for parsing the
job and is ignored for any other pruposes

* add goroutine text profiles to nomad operator debug

* add server-id=all to nomad operator debug

* fix bug from changing metrics from string to []byte

* Add function to return MetricsSummary struct, metrics gotemplate support

* fix bug resolving 'server-id=all' when no servers are available

* add url to operator_debug tests

* removed test section which is used for future operator_debug.go changes

* separate metrics from operator, use only structs from go-metrics

* ensure parent directories are created as needed

* add suggested comments for text debug pprof

* move check down to where it is used

* add WaitForFiles helper function to wait for multiple files to exist

* compact metrics check
Co-authored-by: Drew Bailey <2614075+drewbailey@users.noreply.github.com>

* fix github's silly apply suggestion
Co-authored-by: Drew Bailey <2614075+drewbailey@users.noreply.github.com>

properly wire up durable event count

move newline responsibility

moves newline creation from NDJson to the http handler, json stream only encodes and sends now

ignore snapshot restore if broker is disabled

enable dev mode to access event steam without acl

use mapping instead of switch

use pointers for config sizes, remove unused ttl, simplify closed conn logic

Fixes #9017

The ?resources=true query parameter includes resources in the object
stub listings. Specifically:

- For `/v1/nodes?resources=true` both the `NodeResources` and
  `ReservedResources` field are included.
- For `/v1/allocations?resources=true` the `AllocatedResources` field is
  included.

The ?task_states=false query parameter removes TaskStates from
/v1/allocations responses. (By default TaskStates are included.)

are removed from the event buffer.

Wire up event buffer size config, use pointers for structs.Events
instead of copying.

address pr feedback

* generic eval update event

first pass at alloc client update events

* api/event client