Archive out of date case studies on Drupal.org

Case studies that are older than 5 years should be archived, and an automation put in place that would automate this going forward. This will help keep the content more recent and feature the latest Drupal versions.

This issue was a product of the community summit round tables at DrupalCon.

Notes from round table: https://docs.google.com/document/d/1kmFhypDpHZV4TFTSdXilMuFhYHiI3ZckFPTD...