cleanup: remove docs/, update README & CONTRIBUTING, fix repo config (#13770)

docs/contribution/templates_json/AppName.json

@@ -1,40 +0,0 @@
-{
-  "name": "AppName",
-  "slug": "appname",
-  "categories": [
-    0
-  ],
-  "date_created": "2026-01-18",
-  "type": "ct",
-  "updateable": true,
-  "privileged": false,
-  "interface_port": 3000,
-  "documentation": "https://docs.example.com/",
-  "website": "https://example.com/",
-  "logo": "https://cdn.jsdelivr.net/gh/selfhst/icons@main/webp/appname.webp",
-  "config_path": "/opt/appname/.env",
-  "description": "Short description of what AppName does and its main features.",
-  "install_methods": [
-    {
-      "type": "default",
-      "script": "ct/appname.sh",
-      "resources": {
-        "cpu": 2,
-        "ram": 2048,
-        "hdd": 8,
-        "os": "Debian",
-        "version": "13"
-      }
-    }
-  ],
-  "default_credentials": {
-    "username": null,
-    "password": null
-  },
-  "notes": [
-    {
-      "text": "Change the default password after first login!",
-      "type": "warning"
-    }
-  ]
-}