refactor: move personal site to sites/nrd.sh/

Reorganize for monorepo structure:
- Move content/, templates/, static/, site.toml → sites/nrd.sh/
- Frees root for sukr docs site
- Build with: sukr -c sites/nrd.sh/site.toml

sites/nrd.sh/content/projects/pc.md

@@ -0,0 +1,6 @@
+---
+title: partnerchain
+description: "A Substrate-based blockchain running on top of the Cardano network."
+weight: 0
+link_to: "https://github.com/input-output-hk/partner-chains"
+---