Enhance Open Source Policy Framework Documentation

• Architecture page: Minor Updates
• Design and Development: Add Apex view
• Policy Offered API: Review
• Policy Component Installation page: Review and add Minikube installation steps
• Policy Platform Development Tools: Review and update S3P (Wayne), update Swagger (Davide), Review Prometheus Metrics
• Property-configuration mechanism: Review
• PAP Architecture: Rewritten 
• Clamp Documentation: Rewritten 
• Kafka Strimzi Support Documentation: Add
• The Policy Framework User Interface: Review
• APEX PDP: Review, Installation of Apex: Rewritten, Apex Configuration: Review,  Apex Policy Guide and Policy Example: Rewrite (My First Policy, PCVS delete, Decisionmaker)