Ansible turned 0640 into 420 and 0750 into 488, only one of which are
valid file modes.  Quotes prevent it from doing so too early.
Fixes d2f1595c.

During the edxapp refactor, three tasks were combined, but the modes
were all squished to 0644

* Makes the mysql role a dependency of edxlocal
* Moves memcached install into new role
* Installs memcached if EDXAPP_MEMCACHE contains localhost

It is part of the default AWS AMI though, which is why we haven't
noticed.

When running on a dirty image (such as a sandbox base image or an AMI
build) this clears static files so that collectstatic will copy
everything.

Django's collectstatic copies files and doesn't preserve timestamps,
then only copies "newer modified files".  This leads to a condition
where old static files are in /edx/var/edxapp/staticfiles with a
timestamp of Yesterday, and we add a new dep which comes down from npm
with a timestamp of last week.  Collectstatic will not copy those.

This reverts commit 72461609.

* add splunk searches via ansible

* Fix jinja syntax, add docs

* Add splunk field extractions via ansible

* Use a boolean rather than a number

The fact that splunk uses "1" and "0" to represent booleans is
orthogonal to booleans in yaml. Switching to true booleans for a better
user experience.

* Additional cleanup around splunk searches interface

* Switch splunk role to using common_vars and overrides

This way, we can support environments where we don't, for example, use
datadog.

* Make splunk playbook actually call splunk role

* Fix all the bugs

* Add splunk email config

* Make realtime alerts work

* Add more documentation around splunk alerts

* Address comments

We install the rabbit deb from files.edx.org

I was able to install rabbit and all of its apps at the same
version we have in production without adding the rabbit PPA.

Properly referencing variable.

ECOM-4414