(Merge on 18 Feb) Server 6.9.0 release notes
(Merge on 18 Feb) Server 6.9.0 release notes

This commit adds a new feature note for the Server 6.9.0 release.
puppetlabs/puppet-server,puppetlabs/puppetserver,puppetlabs/puppetserver,puppetlabs/puppet-server,puppetlabs/puppet-server,puppetlabs/puppetserver,puppetlabs/puppetserver