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

README.md

@@ -9,9 +9,9 @@ The Cloudron component focuses on packaging upstream free/libre/open application
 ### 📊 Current Progress
 
 - **Total Applications**: ~57 (see [GitUrlList.txt](GitUrlList.txt))
-- **Completed Packages**: 15/~57 (~26%)
+- **Completed Packages**: 16/~57 (~28%)
 - **Packaging Templates**: Created ✅
-- **Packages Committed & Pushed**: 15 ✅
+- **Packages Committed & Pushed**: 16 ✅
 - **Build Tickets**: 46 filed (#633-#678, umbrella
   [#632](https://projects.knownelement.com/issues/632), Redmine project 55);
   grist-core excluded (packaged upstream)
@@ -37,6 +37,7 @@ The Cloudron component focuses on packaging upstream free/libre/open application
 | 13 | FX | DevOps-Tools | 3.55GB | 8000 | localstorage (auth proxy) | ✅ Committed |
 | 14 | ChirpStack | Infrastructure | 83.4MB | 8080 | localstorage, postgresql, redis | ✅ Committed |
 | 15 | eLabFTW | Business-Apps | ~209MB (compressed) | 443 | localstorage, mysql, ldap | ✅ Committed |
+| 16 | NetBox | Infrastructure | ~1GB | 8080 | localstorage, postgresql, redis | ✅ Committed |
 
 ### 📦 Packages in Development