Update golang to 1.12.9

The dev mode flag for connect was binding to the default interface's
IP, but this makes for a bad user experience for the CLI which will
default to 127.0.0.1. If we bind to 0.0.0.0 instead the CLI will work
without further configuration by the user.

* adds meta object to service in job spec, sends it to consul

* adds tests for service meta

* fix tests

* adds docs

* better hashing for service meta, use helper for copying meta when registering service

* tried to be DRY, but looks like it would be more work to use the
helper function

This removes the in-repository Netlify configuration. There are now two
sites backed by the repository, so we must use the web UI to
control the build settings, as having the configuration in-repository
overrides the web UI settings.

The build settings for the two sites are below, as of this commit. See
the extra step in nomad-ui site’s build step that copies the _redirects
file to the correct destination so things are properly forwarded when
you visit the deployment.

nomad-ui:

base directory: ui
build command: ember build && mkdir -p ui-dist/ui && mv dist/* ui-dist/ui/ && cp ../.netlify/ui-redirects ui-dist/_redirects
publish directory: ui/ui-dist

nomad-website:

base directory: website
build command: bundle exec middleman build
publish directory: website/build

connect: task hook for bootstrapping envoy sidecar

Fixes #6041

Unlike all other Consul operations, boostrapping requires Consul be
available. This PR tries Consul 3 times with a backoff to account for
the group services being asynchronously registered with Consul.

ci: Use more recent base machine executor image for test-rkt

This fixes a frequent failure in `test-rkt` jobs where dpkg installation
fails.

The image used currently, circleci/classic:201808-01, has unattended
upgrades enabled accidentally, which runs on every build.  This means
that tools get modified unexpectedly during builds, and apt-get commands
may fail as the unattended upgrade is holding package database lock.

This updates `test-rkt` job only because the new image breaks
`test-docker` job (e.g. https://circleci.com/gh/hashicorp/nomad/2641 ),
and I punted on investigating test-docker for another day.

remove hidden field from host volumes

We're not shipping support for "hidden" volumes in 0.10 any more, I'll
convert this to an issue+mini RFC for future enhancement.

api: Fix definition of HostVolumeInfo

clientconfig: Fix parsing multiple host volumes

Fine grained ACLs for Host Volumes

This adds a job to test the UI on CircleCI, including the sort of branch
pattern-matching from #5839, so .-ui/ branches only have that job
and not the non-UI ones.

I considered having an entire workflow for UI, which could have separate
jobs for linting vs Ember tests, but the lint commands take so little time
that it didn’t seem worth it.

There’s no use of nvm to change the Node version as the Docker image
is what controls that. It’s annoying to have to update the version in multiple
places, but probably infrequent.

Register connect enabled group services with Consul

Adds a check for differences in `job.Diff` so that task group networks
and services, including new Consul connect stanzas, show up in the job
plan outputs.

Fixes #6042

Add new task group service hook for registering group services like
Connect-enabled services.

Does not yet support checks.

Bump up github.com/hashicorp/go-syslog for better BSD support

add node.region to interpolation documentation

UI: Allocation file system explorer

UI: Use the standard empty message when an fs dir is empty

vendor: update testify to v1.4.0

This lets us turn Mirage logging on without editing any
files, which makes it easier to switch between branches.

Block rpc handling until state store is caught up