Removes `testenv` annotations and related code. These annotations originally let you skip x-pack snippet tests in the docs. However, that's no longer possible.
Relates to #79309, #31619
We no longer regard the autoscaling APIs experimental though they are
only intended for use by ESS/ECE/ECK. This commit updates the docs
to reflect this and adds a minimal set of documentation for the
feature.
Co-authored-by: James Rodewig <40268737+jrodewig@users.noreply.github.com>
This commit merely adds the skeleton for the autoscaling project, adding
the basics to include the autoscaling module in the default
distribution, opt-in to code formatting, and a placeholder for the docs.