Reorganize repo: one folder per application under apps/.

Move docker/ and configs/ into apps/<name>/ with config/ subfolders.
Proxmox split into hosts/pve and hosts/dell-proxmox. Nginx under
infrastructure/. Update sync script, RESTORE.md, and per-app READMEs.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/pgadmin/README.md

@@ -0,0 +1,8 @@
+# pgadmin
+
+| | |
+|---|---|
+| **Poort** | 5434 |
+| **Start** | `docker compose up -d` |
+
+Zie [apps/README.md](../README.md) en [RESTORE.md](../../RESTORE.md).