ARO-23145 - Architectural diagram

[tuxerrante]

Which issue this PR addresses:

Fixes 23145

What this PR does / why we need it:

This PR adds comprehensive architecture diagrams to improve documentation and developer onboarding. The diagrams provide visual representations of the ARO-RP architecture at multiple levels:

1. High-Level Architecture - Shows main services, external dependencies, and data flow
2. Detailed Component Architecture - Illustrates internal components and their interactions within the RP
3. Cluster Lifecycle & Data Flow - Documents the journey of a cluster from creation to running state

Benefits:

• Faster onboarding - New team members can quickly understand the system architecture without diving into code
• Easier code navigation - Developers can identify the right components for modifications by understanding component relationships and responsibilities
• Better design discussions - Visual diagrams facilitate architectural discussions and design decisions
• Reduced knowledge silos - Documentation helps preserve architectural knowledge across team changes

Test plan for issue:

• ✅ Diagrams render correctly in GitHub markdown
• ✅ All components and connections are accurately represented
• ✅ Documentation links are valid and accessible

Is there any documentation that needs to be updated for this PR?

• ✅ Architecture diagrams added to the repository
• Links to relevant documentation included in the diagrams