feat: add NetBox Cloudron package (Infrastructure) [#648]

Official-image wrapper of netboxcommunity/netbox v4.6.10
(netbox-docker 5.0.2, Granian), digest-pinned. OIDC via
python-social-auth wired to the platform provider; RQ worker
backgrounded behind a web-port gate; addon waits cover the 30s
upstream DB timeout. Full-stack verified: migrations, Granian,
worker, login page + SSO button. 16/~57.

Detail + verification: https://projects.knownelement.com/issues/648#note-4976

Package-Workspace/Infrastructure/netbox/CHANGELOG.md

@@ -0,0 +1,13 @@
+# Changelog — NetBox Cloudron Package
+
+## 1.0.0 — 2026-09-06
+
+- Initial package: NetBox 4.6.10 (netboxcommunity/netbox v4.6.10, from
+  netbox-docker 5.0.2), digest-pinned amd64 manifest
+  `sha256:5ee780bd…`
+- Official-image wrapper; Granian web on :8080, RQ worker backgrounded by
+  start.sh after migrations complete
+- postgresql + redis + localstorage addons; tasks DB 0 / caching DB 1
+- Platform OIDC wired via `REMOTE_AUTH_BACKEND` (OpenIdConnectAuth) +
+  `SOCIAL_AUTH_OIDC_*`; local Django login retained for admin bootstrap
+- Persistence: media / reports / scripts / .secret_key under /app/data