(FM-8391) Update README per team practices
(FM-8391) Update README per team practices

This commit updates the readme to remove the language marking litmus
as an experimental tool as well as clarifying the instructions for
running acceptance tests and noting the schedule for the IA Content
office hours.

puppetlabs/puppetlabs-haproxy,puppetlabs/puppetlabs-haproxy,puppetlabs/puppetlabs-haproxy