[Feature branch] Wordpress lite

Post deploy actions:

• Cleanup configuration: #15 (comment 8505717)

Changes:

• Adds CERN Lite Theme via zip installation (https://gitlab.cern.ch/wordpress/theme-lite/-/tags/1.0.0-beta1); optional for existing installation
  • Includes Indico and CDS integration
• Replace local static plugins, configurations and themes with wp installs
• Removes unused themes
• Implement automatic role mapping from OIDC token claims; optional for existing installations
• Enforce plugins: disable-rest-api, cern and OIDC
• Integrate plugins
  • caching: jetpack-boost
  • forms: fluentform and fluent-smtp
  • matomo integration: wp-piwiki
• Fix logout url
• Fix: Configuration replicated on restart on pods
• Add dockercompose and other improvements
• Add makefile and development instructions