feat(docs): restructure documentation with new framework and templates

- Archive old docs to docs-old/ for reference
- Create new top-down documentation structure:
  * Platform Overview: purpose, audience, product structure
  * Components: individual platform components (Forgejo, Kubernetes, Backstage)
  * Getting Started: onboarding and quick start guides
  * Operations: deployment, monitoring, troubleshooting
  * Governance: ADRs, project history, compliance
- Add DOCUMENTATION-GUIDE.md with writing guidelines and templates
- Add component template (TEMPLATE.md) for consistent documentation
- Simplify root README and move technical docs to doc/ folder
- Update test configuration:
  * Exclude legacy content from markdown linting
  * Relax HTML validation for theme-generated content
  * Skip link checking for legacy content in test:links
  * Keep 'task test' clean for technical writers (100% pass)
  * Add 'task test:full' with comprehensive link checking
- Update home page with corrected markdown syntax
- Fix internal links in archived content

BREAKING CHANGE: Documentation structure changed from flat to hierarchical top-down approach

content/en/docs-old/v1/project/plan-in-2024/_index.md

@@ -0,0 +1,42 @@
+---
+title: Plan in 2024
+weight: 30
+description: The planned project workload in 2024
+---
+
+
+## First Blue Print in 2024
+
+Our first architectural blue print for the IPCEI-CIS Developer Framework derives from Humanitecs Reference Architecture, see links in [Blog](../../blog/240823-archsession.md)
+
+![alt text](image-2024-8-14_10-50-27.png)
+
+## C4 Model
+
+First system landscape C4 model:
+
+![c4-model](./planes.png)
+
+## In Confluence
+
+https://confluence.telekom-mms.com/display/IPCEICIS/Architecture
+
+
+## Dimensionierung Cloud für initiales DevFramework
+
+### 28.08.24, Stefan Bethke, Florian Fürstenberg, Stephan Lo
+
+1) zuerst viele DevFrameworkPlatformEngineers arbeiten lokal, mit zentralem Deployment nach OTC in **einen/max zwei** Control-Cluster
+2) wir gehen anfangs von ca. 5 clustern aus
+3) jeder cluster mit 3 Knoten/VM (in drei AvailabilityZones)
+4) pro VM 4 CPU, 16 GB Ram, 50 GB Storage read/write once, PVCs 'ohne limit'
+5) public IPs, plus Loadbalancer
+6) Keycloak vorhanden
+7) Wildcard Domain ?? --> Eher ja
+
+Next Steps: (Vorschlag: in den nächsten 2 Wochen)
+
+1. Florian spezifiziert an Tobias
+2. Tobias stellt bereit, kubeconfig kommt an uns
+3. wir deployen
+