Up till now the ARA plugin has been pinned to a very old version,
and is no longer functional.

This installs a much newer version of ARA and adds a README file
to guide developers on how to view the sqlite file.

The ARA plugin is installed by default, but not activated. This
is intended to catch a small amount of regressions and
integration failures.

Developers can enable the plugin by adding the string `#ara`
to their commit message. This avoids extra load on the CI.

Change-Id: Id8328e374c9590b1363026fa2b2b24e191183987