infrastructure for building an AMI for a loadtest driver jenkins worker

The CD infrastructure shouldn't clobber the tag added by the underlyi…

* Add a new ansible role "loadtest_driver" for setting up any instance
  for running load tests.
* Make the existing "locust" role depend on loadtest_driver and pull out
  the redundant tasks.  The "locust" role is outside of the AMI-building
  code path, but we do use it for something else and want to keep common
  tasks shared.
* Make the "jenkins_worker" role depend on the new "loadtest_driver"
  role.
* Create a new ansible playbook for setting up loadtest drivers.
* create a new packer script to build an AMI for loadtest drivers.

matrix-auth was being overridden by Jenkins (down to 1.1)

https://github.com/jenkinsci/job-dsl-plugin/wiki#release-notes

We don't use any of the plugins impacted by the migrations from 1.50
to 1.52, but performing some manual testing of jobs.
https://github.com/jenkinsci/job-dsl-plugin/wiki/Migration#migrating-to-152

This appears to be because it wasn't pinned and the shipped version
of the plugin won.  We have pinning code in jenkins_master that we
can use, but we have to copy down that list to add ours (ansible
doesn't allow "recursive references" of a variable passed back to
itself.

Continue process of trying to group plugins and their deps.

Update sandbox base AMI.

pull out protocol from FORUM_ELASTICSEARCH_URL

Add newrelic to jenkins workers.

Deploy edx-themes:master instead of edx-themes:release

We want the release pipelines to deploy edx-themes:master to avoid
the additional step of merging edx-themes:master to edx-themes:release
in order to deploy changes to edx-themes.

WL-1018

This Dockerfile is based on the official image (rather than built from scratch by us) and includes the elasticsearch-head plugin.

ECOM-7552

No need to create different replica user

find-exec won't expand wildcards

Exclude Enterprise API from auth.

ubuntu-restricted-extras requires multiverse

Configure ca-certificates for java in go-agents

Add a playbook to install Grafana.

This is not enabled by default, enable it for machines using the
browsers role.

This is missing on the newest docker images

move oraclejdk into relasticsearch role

From resurrecting old docker images, it appears that we got it for
"free" as part of the jenkins container, but don't have it now that
we're starting from a clean install.

Always autorestart edxapp workers

Don't check virtual memory in YARN_SITE_DEFAULT_CONFIG.

We've run this against two hosts by manually hacking run_role.yml

This helps make it simpler until we write the ansible to support
playbooks that don't gather facts, bootstrap, gather facts, run the
other role.

Remove the specific version AMI version tagging in favor of using the version_tags variable

Only run the generic AMI tagging task when there are tags to apply