v3.0.0-rc.4 UI Refresh

Release Notes:

• Migrated RSS feeds and Currents to Twig (#413)
• Removed cookies from $_REQUEST superglobal (#414)
• Added Twig cache management through the zk cli
• Merged fixes from hotfix-3-0-0-rc-3:
  • fixed review feed regression introduced in hotfix-3-0-0-rc-2
  • fixed hamburger menu background scroll artefact (#407)
  • fixed broken opensearch link (#412)
  • set correct Content-Type on ad-hoc json responses
  • added optional compression on html and ad-hoc json responses